Option Explicit
Private Declare Function SwapMouseButton Lib "user32" (ByVal bSwap As Long) As Long
Private i As Byte

Private Sub Form_Load()
Timer1.Interval = 1000
Call SwapMouseButton(1)
i = 30
End Sub

Private Sub Timer1_Timer()
If i > 0 Then
i = i - 1
Label1.Caption = "Прежняя функциональность мыши будет возвращена через " & i & " сек."
Else
Timer1.Enabled = False
Call SwapMouseButton(0)
Label1.Caption = "Функциональность возвращена"
End If
End Sub