Here's a simple easy way to test if your computer is infected with the Conficker B or C worm.
One of the first things that the worm does when it infects your computer is to prevent access to certain websites like antivirus websites. All this test does is see if your PC is somehow blocked from accessing 6 key websites.
Click this link to test your PC:
http://www.confickerworkinggroup.org/infection_test/cfeyechart.html
(Currently, this website is getting a LOT of hits so don't be surprised if it is slow.)
Here's more info about the Conficker Working Group. All of the major antivirus companies are members of the group and also companies like Microsoft, Cisco and AOL.
http://www.confickerworkinggroup.org/wiki/