ck4707,
Lets start with the Guide in the thread:
Guide for Eliminating Spyware, Adware, and Random Popups
If that does not eliminate the problem, then:
Download
Hijack This! and post the log file here. Do
NOT make any repairs. (Hijack This! pulls up everything, including programs that are supposed to be in your computer.)
If you some reason we do not find the problem there, then we update WinXP, IE, and the Hardware Drivers.
Take Care,
Richard