Computers utilize hard disk drives.  Hard disk drives have moving parts and are thus, partially mechanical.  Mechanical devices have a tendancy to break down because they have moving parts.  Sometimes when Windows crashes, it will leave a lost cluster.  Over time, your hard drive will have portions of it go bad an no longer record information accurately.  These bad portions are known as bad sectors.  These bad sectors and lost clusters can cause Windows to perform less than optimally.

This can be fixed by scanning your hard drive.

Instructions:

Run Program "SCANDISK."
SCANDISK usually comes with Windows 95/98 and is usually found under:
/START/PROGRAMS/ACCESSORIES/SYSTEM TOOLS/SCANDISK.

Choose the "Thorough" Scan.

WARNING:  Use this information at your own risk.  There is no implied or stated warranty for accuracy of this information.