SHFormatDrive is an undocumented but simple API function that allows you to format a drive. This function simply opens “Format Drive” diaolog window. Being undocument you won’t find its Declare with the API Viewer utility:
Private Declare Function SHFormatDrive Lib "Shell32.dll" (ByVal hWnd As Long, _ ByVal Drive As Integer, ByVal fmtID As Integer, ByVal Options As Integer) _ As Long
The SHFormatDrive takes four parameters. The first is the handle of the parent window. The second is the index of the drive to be formatted (A=0, B=1, C=2