If your current programme which is installed in your computer, cant pick up teh virus, you should try to first update your current programme. As new virus are created daily, you need to constantly update your software.

You can also try downloading this Virus detector programme for free called LAVASOFT. Quite reputable and you can upgrade to a higher standard if desired :

http://www.lavasoftusa.com/

or try SPYBOT, another well-known FREE download to combat unwanted bugs :

http://www.safer-networking.org/