two viruses--This is Mary

A couple of good general-purpose tools to start with are <a href="http://www.safer-networking.org/">SpyBot</a> and <a href="http://www.lavasoftusa.com/software/adaware/>AdAware</a>, both free for personal use. It's worthwhile to install and run a scan with both of these once a month or so, on general principles.

<a href="http://vil.nai.com/vil/content/v_103539.htm">Here</a> is the NAI page for the "black worm" virus. A more likely candidate is <a href="http://vil.nai.com/vil/content/v_138027.htm">this one</a>, which made a lot of news lately for its particularly nasty payload (overwrites the contents of every Office document it can find on the 3rd of every month). If this is what you have, Symantec has <a href="http://www.symantec.com/avcenter/venc/data/w32.blackmal@mm.removal.tool.html">a tool available</a> to remove specifically that virus, for free.

Hope this helps!