|"I reinstalled XP thinking that she may have had a virus or malware going undetected, but the problem still exists with the new install."|
How did you do this?
Did you format the drive and reinstall Windows, or did you skip formatting the drive?
Did you backup any files before you did this and if so what kind of files.?
When you tried Task Manager is it there but Greyed Out or is it just not showing on the Ctrl+Alt+Del Menu?
When the system does not allow you to run Task Manager then it is because you are on a Domain with Group Policies to prevent you or you have a Virus. I am guessing that you are some how putting the virus back on the system, not formatting the drive, or using an infected systems disk.