My corporate XP box is giving me two forms of the same delayed write error message (image left). They reference two paths:
The only Ultron I know dates to my childhood, it's not a very friendly name for a directory.
Of course it's natural to think about viruses, but I'd have thought there's be some more hits on the topic ...
Update 8/4/09: A virus, after all. Some variant of Win32/ilomo.bc – but one that seems to spread over a network rather than as a trojan.