Hello rdmceachern,
If you do not have a current backup of your valuable files, research the technique of starting the computer with an offline operating system (IOW, one that runs from a CD drive only) to rescue whatever files you need to save to a flash drive, CD drive, external disk, or newtork computer.
Once that's done, use the Dell PC Restore recovery procedure to recover the computer back to out-of-the-box condition. To find out more about this, go to
http://support.dell.com, enter your computer's Service Tag, then look for instructions on how to recover the original Windows installation.
IMO this is the best way to ensure that you have eradicated the virus that may be responsible for this situation.
For great advice on all topics XP, visit http://www.annoyances.org/exec/forum/winxp
