You might consider going for the Windows XP repair option. You insert your XP disk, reboot and repair your installation. You should back up your emails and favorites. It's hard to explain where both are located
FWIW.... http://www.webtree.ca/windowsxp/repair_xp.htm
I think you need some local geek help or you might end up with a real mess. Losing stuff you don't want to lose. AKA hosing your system
Has this system every had a reformat and rebuild?
Or are you running what Dell supplied in the package....??