Keyboard keys are not working after running macro

I used keypress code in one of forms, after running following command non of my keyboard is working in excel. when i am restarting excel everything is fine. what could be the reason?

Private Sub ListBox_KeyPress(ByVal KeyAscii As MSForms.ReturnInteger)
    If KeyAscii = 13 Then
    ......some code here for fetching data from list box
    End if
End Sub

Thanks