[Genius Live]

Use Try

كود :

Try
Process.Start("D:\Al\video\1.mp4")
Catch ex As Exception
MsgBox("This video does not exist")
End Try

Or use System.IO

كود :

If System.IO.File.Exists("D:\Al\video\1.mp4") Then
Process.Start("D:\Al\video\1.mp4")
Else
MsgBox("This video does not exist")
End If