Your personal computer is a curious combination of digital data and temperamental machinery. To keep your system running smoothly, it pays to perform some regular maintenance tasks. In particular, it's wise to do the following on a regular basis:
Check your disks for file system and media errors.
Defragment your hard disks to optimize file access.
Make sure that you always have enough space on your hard disk by getting rid of files you no longer need and compressing files if necessary.
Perform regular backups of data and system files.
Errors in disk media and in the file system ...