Hi Megan, and welcome to Geeks to Go! I think that you will find this place to be a great resource.
PC-Cillin is a good product, and I'm glad that it reports no problems. Unfortunately, there still is no one application (Program) that has shown 100% effectiveness in finding and removing all malware. To be sure that your system is not hosting a "baddie," I suggest that you follow the self-help procedure outlined here:http://www.geekstogo..._Log-t2852.html
If you do find something, please scan again. If the problem persists, please post a HiJackThis log according to the instructions included in the above link. In the meantime, much can be learned about XP in Sam's E-Book: http://www.samspubli...r...4hours&rl=1
You can start at the top and work through, or go to any chapter that seems to be of interest. For what I have learned about gaining control of my system, with links to useful tools and informational sites, please see my Vox: http://doc1101.vox.com/
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