Help, my Toshiba Satelite will not turn off. I tried to shut it down from Windows and the screen is locked up. What should I do?

I also have a four year old Toshiba Satelite that will not turn off from the Windows start menu. The old way for my to shutdown is by holding down the power button. This is not the best way to do things, but it's the only way for me, seeing as the entire system seems to be half-dead anyways.