Question

How can I detect the drive on which the operating system is installed using VB6?

Private Sub GetSystemDrive()
    ' What to write here?
End Sub

Answer 1

Using API calls is slightly more reliable than accessing environment

Private Declare Function GetWindowsDirectory Lib "kernel32" Alias "GetWindowsDirectoryA" (ByVal lpBuffer As String, ByVal nSize As Long) As Long

Private Function GetSystemDrive() As String
    GetSystemDrive = Space(1000)
    Call GetWindowsDirectory(GetSystemDrive, Len(GetSystemDrive))
    GetSystemDrive = Left$(GetSystemDrive, 2)
End Function

Private Sub Form_Load()
    Debug.Print GetSystemDrive
End Sub