Mcafee AVERT stinger is a small tool to detect and remove some widespread worms and viruses, you can download the latest version of the tool here. There is a small tutorial here as well.
Note: This will only scan and remove a small number of widespread viruses and worms, however you will still need to install an ant virus software to prevent further infection.
in my next post I will write about a free anti virus software that's more effective at preventing infections.