Get The Number Of Mouse Buttons

'Add a module to your project (In the menu choose Project -> Add Module, Then click Open)
'Insert this code to the module :

Declare Function GetSystemMetrics Lib "user32" (ByVal nIndex As Long) As Long
Public Const SM_CXSCREEN = 0
Public Const SM_CYSCREEN = 1

'Insert this code to your form:

Private Sub Form_Load()
MsgBox (GetSystemMetrics(SM_CMOUSEBUTTONS))
End Sub