The System Restore utility that comes with Windows lets you restore your computer's settings to an earlier date in case something goes wrong that can't be corrected by any other means.

There are several ways to use System Restore — here are the steps I follow:

Click on Start>All Programs>Accessories>System Tools>System Restore. Click Next until you see a page that resembles this in WinXP:   (Win7 calendar version at bottom of page.)

The calendar will display the current date along with some dates in bold type and some in plain type. The bold dates indicate times to which you can restore your computer's system settings. (The non-bold dates are too far back to be usable.) Click on one of the bold dates to indicate the time to which you want your system restored.

Click Next and your computer will try to accomplish the task. (We say "try" because on rare occasions this procedure cannot be completed properly.)

Continue following the Next prompts until you get a message saying the computer needs to restart in order to complete the task. Wait for the re-boot and everything should be as it was on the date you have chosen.