Option Explicit
Private Declare Function OpenProcess Lib "kernel32" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function EnumProcesses Lib "PSAPI.DLL" (lpidProcess As Long, ByVal cb As Long, cbNeeded As Long) As Long
Private Declare Function EnumProcessModules Lib "PSAPI.DLL" (ByVal hProcess As Long, lphModule As Long, ByVal cb As Long, lpcbNeeded As Long) As Long
Private Declare Function GetModuleBaseName Lib "PSAPI.DLL" Alias "GetModuleBaseNameA" (ByVal hProcess As Long, ByVal hModule As Long, ByVal lpFileName As String, ByVal nSize As Long) As Long
Private Const PROCESS_VM_READ = &H10
Private Const PROCESS_QUERY_INFORMATION = &H400
 
Private Function EstaCorriendo(ByVal NombreDelProceso As String) As Boolean
    Const MAX_PATH As Long = 260
    Dim lProcesses() As Long, lModules() As Long, N As Long, lRet As Long, hProcess As Long
    Dim sName As String
    NombreDelProceso = UCase$(NombreDelProceso)
    ReDim lProcesses(1023) As Long
 
    If EnumProcesses(lProcesses(0), 1024 * 4, lRet) Then
        For N = 0 To (lRet \ 4) - 1
            hProcess = OpenProcess(PROCESS_QUERY_INFORMATION Or PROCESS_VM_READ, 0, lProcesses(N))
            If hProcess Then
                ReDim lModules(1023)
                If EnumProcessModules(hProcess, lModules(0), 1024 * 4, lRet) Then
                    sName = String$(MAX_PATH, vbNullChar)
                    GetModuleBaseName hProcess, lModules(0), sName, MAX_PATH
                    sName = Left$(sName, InStr(sName, vbNullChar) - 1)
 
                    If Len(sName) = Len(NombreDelProceso) Then
                        If NombreDelProceso = UCase$(sName) Then EstaCorriendo = True: Exit Function
                    End If
                End If
            End If
            CloseHandle hProcess
        Next N
    End If
End Function
 
Private Sub Command1_Click()
    If EstaCorriendo("calc.exe") Then
         MsgBox "El programa está en ejecución"
    Else
         MsgBox "El programa NO está en ejecución"
    End If
End Sub