First, try to unfreeze using a keyboard command. PC users: Hold down the Ctrl, Alt, and Delete buttons to call up a window called Task Manager; with your arrow keys, select the option that says "Not Responding" and click on the End Task button. With a Mac, press the Apple key, Option, and Escape. If your mouse is the culprit, doing this will usually thaw the freeze.

If keyboard commands don't do the trick, then your keyboard is frozen, too. Reboot via the power switch, and run your computer's included fix-it software: ScanDisk on PCs, Disk First Aid on Macs. These two helpers can solve most ordinary glitches that cause freezes. In Windows, look under Programs> Accessories>System>Tools; on Macs, look in the Utilities folder.

Freezes can be warnings that you are low on disk space. In Windows, check how much space you have by highlighting the C: drive (the hard drive), right-clicking, and selecting Properties. On a Mac, highlight the hard-disk icon and hold down the Apple and I keys. If you have less than 500 megabytes of storage left, start deleting software you don't use anymore and transfer old files to backup disks.