I use windows vista as operating system, but after the new installation of Vista my computer show me Windows security center give me error popup like file atapi.sys has been attacked by a Trojan. That time I installed windows 7. AVG. but windows keeps popping then I use McAfee antivirus but then also I get this virus, after the installation of McAfee antivirus I update also. But still it will give me error. so tell me what should I do? How I remove virus from atapi.sys file?