I fully scanned my computer and found nothing. But whenever i insert my clean usb flash disk, nod32 constanly warns me of Win32\Agent.NEF. It seems that nod32 is deleting the newly generated virus repeteatedly. And I can not find something unusual in the ESI log. Could any one help? The basic information of that virus is not available in eset threat encyclopedia so its hard to remove it mannually. Why ESET can not detect an already known virus in an infected computer?