I personally do not like registry "repair" programs, I've seen cases where the "repair" had caused more problems than it fixed.

With some viruses, even tho they are "cleaned" they can still leave behind fragments or cause system file problems.  Unfortunately Dell is probably correct that it will take a "clean" install to correct everything.  With the complexity of current Operating Systems trying to fix some problems is almost impossible.  

The proper installation sequence for a "clean install" is to (1) boot from the Windows XP CD and select the option to reformat the hard drive, then continue with the Operating System Installation (2) install the Dell chipset drivers (3) install any other Dell device drivers (4) Install any Dell applications programs that you want (5) Install your own software and restore your backed up user data (back up the user data before you start the clean install, which includes the My Documents folder, your E-mail account and address book, Internet Explorer favorites and any other user data that you will need to recover).

Thanks that is helpful. I think I might try a USB modem first before an XP reinstall: all my USB devices work OK so its worth a try.