Quote: "but in that case, would it start up at all?"
It should do. I've had loads of clashes from one thing or other over the years, and nothing stopped the machine from booting.
I wouldn't have thought it was a virus. And I can't believe it's a badly fragged disk unless you have like zero space left. Computers have too much space, and are too fast to have that much effect without defrag. Leave a machine unfragged for several years then defrag it. It will *not* go from several minutes on boot up to several secs. Trust me, I've used machines like that. And unless it's a corrupt file, then I've never heard of adware that screws your machine up so badly.
My guess would be conflicts, or hardware problems (HD not winding up properly with stuffed belt for example). Or possibly corruption. Which could also be self inflicted eg. mucking around with registry or manually removing files. I've seen slow boot ups due to missing files (auto load programs keep trying to load something that doesn't exist until they reach a timeout).
Have you installed anything lately (good olde mag demos can be suspect)? Or updated any hardware? How about mucking around with any windows settings? Esp removing unwanted files or registry entries.
Of course the obvious last resort (or first resort in 9X case) is just to reinstall. Back it all up and wipe the lot. Nice new clean feeling.
Cheers
I am 99% probably lying in bed right now... so don't blame me for crappy typing
