If you are a Windows user then you will hopefully be familiar with the Conficker Worm threat.
And equally hopefully you will be taking appropriate precautions against infection. You must at least have a proper Anti Virus application installed and running, and keep it up to date. Most will offer regular updates to the virus database, often daily.

There is another weapon you can use against Conficker and this one is free and effective, and doesn’t involve installing anything on your PC.

Open DNS is currently blocking access to all domains that the worm tries to phone home to. At the last count that was 50,000.
By blocking this access the worm becomes useless as it can’t connect back to the botnet.

All you have to do is replace the DNS settings in your router with those of Open DNS, and instructions on how to do this can be found on their website.

The DNS servers you currently use will probably be those of your ISP, and may be dynamically assigned. This means you didn’t have to manually enter them. Uncheck the appropriate option on your router and enter the OpenDNS settings.

If you want to disinfect your computer I recommend you check out the tools at Kaspersky Lab.