Any program that crashed or simply "misbehaved" could make Windows 3.x unstable. Also, if information was being written to the hard disk when these incidents occur , lost clusters on the disk get created. Lost clusters cause valuable disk space to be taken up by unusable information.

Windows 95's protected environment keeps programs from crashing the system. Microsoft ScanDisk, which comes with Windows 95, allows you to check the disk's surface, files, and folders for lost clusters and correct them if they exist, thus freeing disk space by getting rid of unusable information. Checking for these errors ahead of time can also prevent data loss problems.

Microsoft ScanDisk existed before Windows 95 as an MS-DOS 6.x utility, but it is new to Windows. Windows 95 includes a new Windows version and a new MS-DOS version. The MS-DOS version is used during Windows 95 setup, and you can use it if you need to run ScanDisk in MS-DOS mode (discussed later). The Windows ScanDisk version can be run in the background while other Windows programs are running. ScanDisk offers you two checking options: Standard and Thorough. Standard checks the files and folders on the selected drive or drives for errors. Thorough does the same thing and checks the physical integrity of the disk's surface.

If, for instance, you select the c:\ drive for a standard test, however, ScanDisk does not check:

• configured CD-ROM drives
• network drives
• drives created by the MS-DOS commands ASSIGN, SUBST, JOIN and INTERLNK

ScanDisk does check:

• local hard drives
• floppy drives
• RAM drives and memory cards
• mounted drives that are compressed with Microsoft DoubleSpace or DriveSpace

The MS-DOS version included in Windows 95 can also check unmounted drives compressed with DoubleSpace or DriveSpace but it cannot check for long file name integrity. As a rule, you should use the Windows version of ScanDisk first and the MS-DOS version if you still need to correct other problems.

When ScanDisk finishes checking, it reports on errors found and summarizes information about the disk, like the MS-DOS CHKDSK utility. If it finds errors, ScanDisk issues a prompt asking if you want to repair the disk area and/or save its information to a file.

Run ScanDisk on a regular basis: it's always a good idea to check for errors and fix them before data loss occurs. One easy way to run it is to place a shortcut in the start-up group and use the following command line parameters to check drives automatically every time you start your computer.

1. Add the ScanDisk icon to your StartUp folder and use your right mouse button to click the icon.
2. Click Properties, and then click the Shortcut tab.
3. After the text in the Target box, specify one or more of the following:

drive: to specify the drive(s) you want to check

/a to check all your local, nonremovable hard disks

/n to start and close ScanDisk automatically

/p to prevent ScanDisk from correcting any errors it finds

Examples

To check drive D and start and close ScanDisk automatically, the text in the Target box should look similar to the following:

c:\windows\scandskw.exe d: /n

To check all nonremovable hard disks but prevent ScanDisk from correcting any errors it finds, the text in the Target box should look similar to the following:

c:\windows\scandskw.exe /a /p