If running XP then you MUST disable System Restore first:
Bad eyes. The trojan horse infecting my system is do.exe, not go.exe as I first reported. After leaving computer running for a long time I am returning to find the NAV 2002 warning screen up and identifying do.exe as a Trojan Horse that cannot be repaired but which has been quaranteed. There are two new icons on the desktop which I can drag to the recycle bin and delete and then I can remove do.exe from the NAV quaranteed list. On restart the TH re-establishes itself. How do I delete it permanently? How did I get it as I opened no emails except from trusted senders? Once it is in quarantee can I email others safely to ask them to check their computers?