Microsoft's Malicious Software Removal Tool is a good tool to use to find out if you have been infected by one of many. If you already have Microsoft's automatic windows update tool on and running, then you are probably safe as it will download and run in the background once a month. Make sure that you have the latest version and follow the instructions below:

Right-click on an empty portion of your desktop

Select "new" then "shortcut"

Under 'Type the location...' type in "MRT.exe", capitalize "MRT"

Under 'Type a name...' use any name that will help you remember it

Click Finish

You are now ready to launch the tool. Double click on the icon on your desktop that you just created. We recommend that you run the full scan in order to be safe, but if time constraints are an issue, a quick scan will work.

Happy hunting!