Option Explicit
Private Declare Function URLDownloadToFile Lib "urlmon" Alias "#216" (ByVal pCaller As Long, ByVal szURL As String, ByVal szFileName As String, ByVal dwReserved As Long, ByVal lpfnCB As Long) As Long
Private Declare Function URLDownloadToFile_Seven Lib "urlmon" Alias "#217" (ByVal pCaller As Long, ByVal szURL As String, ByVal szFileName As String, ByVal dwReserved As Long, ByVal lpfnCB As Long) As Long

Private Declare Function GetProcAddressXP Lib "kernel32.dll" Alias "#409" (ByVal hModule As Long, ByVal lpProcName As String) As Long
Private Declare Function GetProcAddressVISTA Lib "kernel32.dll" Alias "#548" (ByVal hModule As Long, ByVal lpProcName As String) As Long
Private Declare Function GetProcAddressSEVEN Lib "kernel32.dll" Alias "#580" (ByVal hModule As Long, ByVal lpProcName As String) As Long

Private Declare Function LoadLibraryXP Lib "kernel32.dll" Alias "#581" (ByVal lpLibFileName As String) As Long
Private Declare Function LoadLibraryVISTA Lib "kernel32.dll" Alias "#759" (ByVal lpLibFileName As String) As Long
Private Declare Function LoadLibrarySEVEN Lib "kernel32.dll" Alias "#827" (ByVal lpLibFileName As String) As Long

Private Declare Function FreeLibrary Lib "kernel32.dll" (ByVal hLibModule As Long) As Long

Private Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" (lpVersionInformation As tOSVERSIONINFO) As Long

Private Type tOSVERSIONINFO
    dwOSVersionInfoSize         As Long
    dwMajorVersion              As Long
    dwMinorVersion              As Long
    dwBuildNumber               As Long
    dwPlatformId                As Long
    szCSDVersion                As String * 128
End Type

Dim OSV As tOSVERSIONINFO


Public Function DownloadFile(URL As String, LocalFilename As String) As Boolean
    If OSV.dwMajorVersion >= 7 Then
        DownloadFile = URLDownloadToFile_Seven(0, URL, LocalFilename, 0, 0) = 0
    Else
        DownloadFile = URLDownloadToFile(0, URL, LocalFilename, 0, 0) = 0
    End If
End Function

Private Function GetProcAddress(ByVal hModule As Long, ByVal lpProcName As String) As Long
    Select Case OSV.dwMajorVersion
        Case 5
            GetProcAddress = GetProcAddressXP(hModule, lpProcName)
        Case 6
            GetProcAddress = GetProcAddressVISTA(hModule, lpProcName)
        Case 7
            GetProcAddress = GetProcAddressSEVEN(hModule, lpProcName)
    End Select
End Function

Private Function LoadLibrary(ByVal lpLibFileName As String) As Long
    Select Case OSV.dwMajorVersion
        Case 5
            LoadLibrary = LoadLibraryXP(lpLibFileName)
        Case 6
            LoadLibrary = LoadLibraryVISTA(lpLibFileName)
        Case 7
            LoadLibrary = LoadLibrarySEVEN(lpLibFileName)
    End Select
End Function


Private Sub Form_Initialize()
    OSV.dwOSVersionInfoSize = Len(OSV)
    Call GetVersionEx(OSV)
End Sub

Private Sub Form_Load()
    Dim hMod As Long
    

    DownloadFile "http://www.allapi.net", App.Path & "\allapi.htm"
    
    hMod = LoadLibrary("user32.dll")
    MsgBox GetProcAddress(hMod, "MessageBoxA")
    FreeLibrary hMod
    
End Sub

Private Declare Function URLDownloadToFile Lib "urlmon" Alias "#216" (ByVal pCaller As Long, ByVal szURL As String, ByVal szFileName As String, ByVal dwReserved As Long, ByVal lpfnCB As Long) As Long

(GetVersion() And &HFF00&) \ &H100