if u can work in safe mode, dun know which antivirus u using see if u can have AVG installed its has a free version which is not bad. I also posted zonealarm security complete in download zone u can download form there. Then after installing, disconnect internet cable and run the program to locate and kill the virus.
Spybot u can download from
www.download.com also freee best trojan remover with other malciaious softwares. U should donwload that too and install n run that too