You have the sasser worm on your pc. Download AdAware Personal SE and/or SpyBot Search and Destroy. They are both free. Install them and do an update and then run them.
I also agree with answer 1 that you should install a firewall to prevent further infestation. There are some very good free and commercial ones out there. I personally use ZoneAlarm.
Here are some links to the apps mentioned above:
AdAware: http://www.lavasoftusa.com/software/adaware/
SpyBot: http://www.safer-networking.org/en/index.html
ZoneAlarm: http://www.zonelabs.com/store/content/company/products/znalm/freeDownload.jsp?lid=staticcomp_za
We've all been through this.
Cheers.
RW