The best way to protect your computer is to have an up-to-date virus checker installed on your computer, and to update the program's virus definitions at least once a month. If you need information about a virus, go to the excellent virus information sites provided at www.symantec.com and www.mcafee.com.
If you don't have virus checking software, you can get virus checking for free online at http://housecall.antivirus.com/. I haven't tried this service, but it looks pretty good. I wonder how they make their money.