:confused: I want to reinstal XP program in my laptop XP HEdition .it comes with cds system and recovery . I read the instructions it tells me to do a back up. My question is How important is it to do a back up? What should I back up?
Also when I do that should I rewrite in hd or formatted?
Thank you

First question would be "why do you need to reinstall XP?"
Virus recovery? Too much junk clogging things up?

Most cases, not including a virus or malicious intrusion, a system simply needs to be cleaned up. "Disk Cleanup", "Disk Defragmenter", and simply uninstalling unused programs via the "add or remove programs" option does the trick. I would need more specifics about your situation to further elaborate on what would help you there.

As for backups, they do serve an important role. Anytime I get ready to install a new program, or before doing a disk defrag, I will do a backup of the system files. That way, if something goes wrong with the new software or there's an incompatibility, and I loose a system file in the process of uninstalling the problem software, I have a backup to restore from.

The importance of having regular backups varies depending on your use, and your available network. If you have a high speed connection that stays connected all the time, then I would at least do a backup every quarter, or every three months. Staying connected online allows you to be potentially vulnerable to hacker attack of one form or another. If you use this computer for business purposes, then I'd backup on a monthly basis.

:confused: I just want to clean up the system,I don't have a virus problem.I have been doing "Disk cleanup", "Disk Defragmenter" and "add or remove programs" over time but never back up.The hd is 40g is parted.one side is almost over .It is a ACER ASPIRE 3500 XP Home Edition . Just ACER itself comes with too many programs or applications that I don't use ;if there is a way how to remove these it will be awesome ,or how to disable these programs in the task manager.