When the time comes that your computer freezes -- you can't seem to do anything at all! -- the first step is to realize that you probably didn't do anything wrong at all. Sometimes, it just happens.

Then, try this:

Press the Ctrl and Alt keys at the same time and hold them down while tapping once on the Delete key. Hopefully, the Close Program box will appear and one of the programs will be highlighted. This program is the one causing your problem. Click the End Task button. That one program will close. Ideally, you should be able to carry on although you may have lost any work in that program that had not been saved. If, however, your system is still locked up, repeat these steps. You could try clicking the Shut Down button in your Close Program dialog box instead of End Task. If this works, your system will safely shutdown.

If that doesn't fix your problem, try restarting your computer by pressing Ctrl+Alt and Delete twice - or press your Reset button on your system.

As a last resort, find the power button and turn the whole thing off! Most of the time this will not harm your system especially if you've tried everything else. Wait 20 seconds then turn your computer on.