Use the Dell supplied recovery media or method to go back to factory conditions. This will include the drivers.
Then reinstall all your applications, redo all your settings and restore all your documents from the backup.
Kees
Please any ideas on
1. how best to re-install XP, and
2. will this correct my sluggish pc?
Dell Optiplex GX520 purchased refurb Sept. '09; upgraded with 500 GB Caviar Green internal hard drive, RAM increased to 2 GB; operated fine until a few months ago; problems with sluggish, takes firefox two minues to open, if at all; oftentimes have to use task mgr to cut process firefox.exe before program will open. Also slow to open iTunes, explorer 7, any program at all. ran speed test DSLreports.com flash test...firefox couldn't get through the test, warning script from movie may crash firefox unless stopped; but no movie running. Explorer could do flash test fine, ~ 9 mbs on comcast internet.
I uninstalled all Adobe programs, and firefox...reinstalled them; but continue to get same warning box and crashing.
Have run rkill by grimler; then malwarebytes; then superantispyware; only needed two rounds before nothing detected.
Now it appears i need to reformat hard drive and reinstall XP PRo; trying to determine best way to do while retaining some programs and settings. have backed up with Acronis free trial; also, backup with XP program; also, have backed up with iomega ProTeckt program; but not sure how many, if any, programs and settings to recover once i reformat and reinstall XP. have searched forums and google,m Westerd Digital site, iomega site, just confusing as to best way to reinstall without having to reload all programs, settings, drivers, etc. for hours.
Any suggestions?
thanks so much, pdoyle.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic