It never HAS had a trojan. Its nothing more than a FALSE POSITIVE with some anti-virus programs. You actually re-formatted your harddrive for what you thought was a trojan? Next time, try getting a 2nd opinion before going to that extreme... such as using a different anti-viral. Or contacting the company that made yours and checking with them on it. They can usually come up with a fix for false positives, but only if they know about it.