Anyone who has a problem should do the following if MacMahooon's suggestion doesn't work. Print out the instructions if you have to because you'll be shutting off your interwebz.
1. Download AVG Free and install it. Get it from
http://free.avg.com/ Let the application update itself.
2. Restart in safe mode. In Windows XP and previous OSes, go to Start->Run and type msconfig. The System Configuration Utility will popup. Select the BOOT.INI tab. Under Boot Options, select /SAFEBOOT. Click ok and shutdown your computer.
3. Unplug your computer from the internet and turn your machine on.
4. Run a full virus scan with AVG and see if it finds anything. If it doesn't, go to Start->Run and type regedit. This will drop you into your registry editor. In the tree on the left, navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion and click on the Run folder once. This will show a list of all the startup items for your account. Take a screenshot and save it to your desktop so you can post it back in this thread. Do the same thing for
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
Some of these registry folders might not exist. That's normal
Search google for "how to screenshot windows"
5. When the scan is over, go to Start->Run and type msconfig. Select the BOOT.INI tab and uncheck /SAFEMODE. Restart and you should be ok.
If this doesn't fix the problem or the problem comes back, post your screenshots of the registry as noted in step 4.