...
Dim escritor As StreamWriter
escritor = File.AppendText(ruta)
...

• How to: Add or Remove Resources | MSDN

#Region " Imports "
 
Imports System.IO
 
#End Region
 
#Region " Resource Util "
 
Namespace ElektroKit.Core.Application.Resources.Tools
 
    Partial Public NotInheritable Class ResourceUtil
 
#Region " Public Methods "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Extracts a resource to disk.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <example> This is a code example.
        ''' <code>
        ''' ExtractResourceToDisk(My.Resources.MyTextfile, "C:\File.txt")
        ''' </code>
        ''' </example>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="resource">
        ''' The resource to extract.
        ''' </param>
        ''' 
        ''' <param name="filepath">
        ''' The target filepath where to save the resource data.
        ''' </param>
        ''' 
        ''' <param name="overwrite">
        ''' If set to <see langword="True"/>, overwites any existing file, 
        ''' otherwise, and if the file already exists, a <see cref="IOException"/> exception is thrown.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerStepThrough>
        Public Shared Sub ExtractResourceToDisk(ByVal resource As Byte(),
                                                ByVal filepath As String,
                                                ByVal overwrite As Boolean)
 
            Dim fileMode As FileMode
            If (overwrite) Then
                fileMode = FileMode.Create
            Else
                fileMode = FileMode.CreateNew
            End If
 
            Dim bufferSize As Integer = 8192 ' 8 kb.
            Using fs As New FileStream(filepath, fileMode, FileAccess.Write, FileShare.Read, bufferSize)
                fs.Write(resource, 0, resource.Length)
            End Using
 
        End Sub
 
#End Region
 
    End Class
 
End Namespace
 
#End Region

ResourceUtil.ExtractResourceToDisk(My.Resources.Program1, "C:\Program1.exe", overwrite:=True)
Process.Start("C:\Program1.exe", arguments:="")

#Region " Imports "
 
Imports System.Reflection
Imports System.Security
Imports System.Security.Permissions
 
#End Region
 
#Region " Resource Util "
 
Namespace ElektroKit.Core.Application.Resources.Tools
 
    Partial Public NotInheritable Class ResourceUtil
 
#Region " Public Methods "
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Loads a resource in memory and executes its main entrypoint.
        ''' <para></para>
        ''' The resource must be a .NET assembly.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <example> This is a code example.
        ''' <code>
        ''' Execute(My.Resources.MyProgram)
        ''' </code>
        ''' </example>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="resource">
        ''' The resource to execute.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <exception cref="EntryPointNotFoundException">
        ''' Entrypoint not found in the specified resource. Are you sure it is a .NET assembly?
        ''' </exception>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerStepThrough>
        Public Shared Sub Execute(ByVal resource As Byte())
            ResourceUtil.Execute(resource, Nothing)
        End Sub
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Loads a resource in memory and executes its main entrypoint.
        ''' <para></para>
        ''' The resource must be a .NET assembly.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <example> This is a code example.
        ''' <code>
        ''' Execute(My.Resources.MyProgram, {"Parameter 1", "Parameter 2", "etc..."})
        ''' </code>
        ''' </example>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="resource">
        ''' The resource to execute.
        ''' </param>
        ''' 
        ''' <param name="parameters">
        ''' The parameters to pass to the method executed.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <exception cref="EntryPointNotFoundException">
        ''' Entrypoint not found in the specified resource. Are you sure it is a .NET assembly?
        ''' </exception>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerStepThrough>
        Public Shared Sub Execute(ByVal resource As Byte(), ByVal parameters As Object())
            Dim helper As New ExecuteHelper()
            helper.LoadAssembly(resource, parameters)
        End Sub
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Loads a resource in memory and executes its main entrypoint.
        ''' <para></para>
        ''' The resource must be a .NET assembly.
        ''' <para></para>
        ''' If the loaded assembly attempts to force an application termination 
        ''' by for example internaly calling <see cref="Environment.Exit"/>, then the call is catched and ignored. 
        ''' <para></para>
        ''' The downside is that the loaded assembly will not be able to call (P/Invoke) unmanaged code. You are advised.
        ''' <para></para>
        ''' *** Note that this is a experimental methodology. ***
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <example> This is a code example.
        ''' <code>
        ''' ExecuteSafe(My.Resources.MyProgram)
        ''' </code>
        ''' </example>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="resource">
        ''' The resource to execute.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <exception cref="EntryPointNotFoundException">
        ''' Entrypoint not found in the specified resource. Are you sure it is a .NET assembly?
        ''' </exception>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerStepThrough>
        Public Shared Sub ExecuteSafe(ByVal resource As Byte())
            ResourceUtil.ExecuteSafe(resource, Nothing)
        End Sub
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Loads a resource in memory and executes its main entry point.
        ''' <para></para>
        ''' The resource must be a .NET assembly.
        ''' <para></para>
        ''' If the loaded assembly attempts to force an application termination 
        ''' by for example internaly calling <see cref="Environment.Exit"/>, then the call is catched and ignored.
        ''' <para></para>
        ''' The downside is that the loaded assembly will not be able to call (P/Invoke) unmanaged code. You are advised.
        ''' <para></para>
        ''' *** Note that this is a experimental methodology. ***
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <example> This is a code example.
        ''' <code>
        ''' ExecuteSafe(My.Resources.MyProgram, {"Parameter 1", "Parameter 2", "etc..."})
        ''' </code>
        ''' </example>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="resource">
        ''' The resource to execute.
        ''' </param>
        ''' 
        ''' <param name="parameters">
        ''' The parameters to pass to the method executed.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <exception cref="EntryPointNotFoundException">
        ''' Entrypoint not found in the specified resource. Are you sure it is a .NET assembly?
        ''' </exception>
        ''' ----------------------------------------------------------------------------------------------------
        <DebuggerStepThrough>
        Public Shared Sub ExecuteSafe(ByVal resource As Byte(), ByVal parameters As Object())
 
            ' This is where the main executable resides. For more info on this, see the "Remarks" section at:
            ' http://msdn.microsoft.com/en-us/library/system.appdomainsetup.applicationbase(v=vs.110).aspx#Anchor_1
            Dim adSetup As New AppDomainSetup()
            adSetup.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory
 
            ' Permissions of the AppDomain/what it can do.
            Dim permission As New PermissionSet(PermissionState.None)
            With permission
                ' All SecurityPermission flags EXCEPT UnmanagedCode, which is required by Environment.Exit() method.
                .AddPermission(New SecurityPermission(SecurityPermissionFlag.AllFlags And Not SecurityPermissionFlag.UnmanagedCode))
                .AddPermission(New EnvironmentPermission(PermissionState.Unrestricted))
                .AddPermission(New EventLogPermission(PermissionState.Unrestricted))
                .AddPermission(New FileDialogPermission(PermissionState.Unrestricted))
                .AddPermission(New FileIOPermission(PermissionState.Unrestricted))
                .AddPermission(New GacIdentityPermission(PermissionState.Unrestricted))
                .AddPermission(New IsolatedStorageFilePermission(PermissionState.Unrestricted))
                .AddPermission(New KeyContainerPermission(PermissionState.Unrestricted))
                .AddPermission(New PerformanceCounterPermission(PermissionState.Unrestricted))
                .AddPermission(New PrincipalPermission(PermissionState.Unrestricted))
                .AddPermission(New ReflectionPermission(PermissionState.Unrestricted))
                .AddPermission(New RegistryPermission(PermissionState.Unrestricted))
                .AddPermission(New SiteIdentityPermission(PermissionState.Unrestricted))
                .AddPermission(New StorePermission(PermissionState.Unrestricted))
                .AddPermission(New TypeDescriptorPermission(PermissionState.Unrestricted))
                .AddPermission(New UIPermission(PermissionState.Unrestricted))
                .AddPermission(New UrlIdentityPermission(PermissionState.Unrestricted))
                .AddPermission(New ZoneIdentityPermission(PermissionState.Unrestricted))
            End With
 
            ' Our sandboxed AppDomain.
            Dim domain As AppDomain = AppDomain.CreateDomain("SomeGenericName", Nothing, adSetup, permission, Nothing)
 
            Try
                ' Create an instance of Helper in the sandboxed AppDomain.
                Dim helper As ExecuteHelper = DirectCast(domain.CreateInstanceAndUnwrap(GetType(ExecuteHelper).Assembly.FullName, GetType(ExecuteHelper).FullName), ExecuteHelper)
                helper.LoadAssembly(resource, parameters)
 
            Catch ex As TargetInvocationException When (ex.InnerException.GetType() = GetType(SecurityException))
                ' Some kind of permissions issue occured here, possibly an attempt to call Environment.Exit() or call (P/Invoke) unmanaged code.
                ' Do Nothing.
 
            Catch ex As Exception
                Throw
 
            End Try
 
        End Sub
 
#End Region
 
    End Class
 
    ''' ----------------------------------------------------------------------------------------------------
    ''' <summary>
    ''' A class that serves to execute assemblies that are stored as application resource (eg. My.Resources.MyProgram1 )
    ''' </summary>
    ''' ----------------------------------------------------------------------------------------------------
    Friend NotInheritable Class ExecuteHelper : Inherits MarshalByRefObject
 
        ''' ----------------------------------------------------------------------------------------------------
        ''' <summary>
        ''' Loads the assembly.
        ''' </summary>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <param name="bytes">
        ''' The bytes of the assembly/resource to execute.
        ''' </param>
        ''' 
        ''' <param name="parameters">
        ''' The parameters to pass to the method executed.
        ''' </param>
        ''' ----------------------------------------------------------------------------------------------------
        ''' <exception cref="EntryPointNotFoundException">
        ''' Entrypoint not found in the specified resource. Are you sure it is a .NET assembly?
        ''' </exception>
        ''' ----------------------------------------------------------------------------------------------------
        Public Sub LoadAssembly(ByVal bytes As Byte(), ByVal parameters As Object())
            Dim ass As Assembly = Assembly.Load(bytes)
            Dim method As MethodInfo = ass.EntryPoint
 
            If (method IsNot Nothing) Then
                Dim instance As Object = ass.CreateInstance(method.Name)
                method.Invoke(instance, parameters)
                If (instance IsNot Nothing) AndAlso (instance.GetType().GetInterfaces.Contains(GetType(IDisposable))) Then
                    DirectCast(instance, IDisposable).Dispose()
                End If
                instance = Nothing
                method = Nothing
                ass = Nothing
 
            Else
                Throw New EntryPointNotFoundException("Entrypoint not found in the specified resource. Are you sure it is a .NET assembly?")
 
            End If
        End Sub
 
    End Class
 
End Namespace
 
#End Region

ResourceUtil.Execute(My.Resources.Program1, parameters:=Nothing)

ResourceUtil.ExecuteSafe(My.Resources.Program1, parameters:=Nothing)

si , pero si por lo menos quiero guardar ese bat con codificación ANSI .
seria algo como esto?

Código

 Dim ruta As String = dirPath & "usb.bat"
            Dim escritor As StreamWriter
            escritor = (File.AppendText(ruta, True, System.Text.ASCIIEncoding.ASCII.GetEncoding))
            escritor.Write(TextBox1.Text)
            escritor.Flush()
            escritor.Close()

aun así me marca error. no logro guardarlo en ansi.  

tampoco lo logro con :  Encoding.GetEncoding(1252) creo que lo estoy escribiendo mal-

File.AppendAllText("C:\Archivo.bat", "contenido del bat", Encoding.Default)

File.AppendAllText("C:\Archivo.bat", "contenido del bat", Encoding.GetEncoding(1252))

Using sw As New StreamWriter("C:\Archivo.bat", append:=False, encoding:=Encoding.Default, bufferSize:=8192)
    sw.AutoFlush = True
    sw.Write("Contenido del bat")
End Using