ScanDisk is a free utility provided by Microsoft with certain versions of MS-DOS and with Windows 95. It's a good idea to run ScanDisk about once a month for preventive maintenance, and it should always be a first check whenever your system starts showing any unusual behaviors.

If you have Windows 95:

1. Go to the Start button.
2. Go to the Programs folder.
3. Go to the Accessories folder.
4. Go to the System Tools folder.
5. Click on ScanDisk.
6. In ScanDisk, make sure all of your hard drives are highlighted. Select Standard for type of test, and check the box next to Automatically Fix Errors. Then click the Start button.

If you have Windows 3.1x:

1. Close Windows and go to the DOS prompt.
2. Type SCANDISK and hit <Enter>.
3. If you see the message "Bad command or file name," then type CHKDSK /F and hit <Enter>.
4. If ScanDisk reports problems, let it fix them. We recommend that you Delete file fragments and Skip Undo.
5. When you are asked to perform a surface scan, you may say No if you don't want to spend the time at the moment. (Running a surface scan once every couple of months is a good maintenance procedure.)

If ScanDisk reports errors, try deleting the malfunctioning program from your hard drive and reinstalling it from the original disk.