If you think it may be a virus then the first thing to do you be to get a virus scanner. (www.grisoft.com
-for a free one).
Once you've determined that there are no viruses then you should scan again for spyware, if you find Adaware keeps stopping anf not responding -for long periods of time, then you could consider giving Spybot Search and Destroy a go when searching.
luto is right if ou are using windows 98 first edition thi could be a part of your problem, but upgrading to second edition would be a lot better than going to ME.