TheVrolok, when you install adaptec, it slips a thing called the ASPI layer, its a set of burner drivers, into the registry.
Older ver's of adaptec put in a layer thats incompatible with win2k, thus your prob.
You'll have to get into safe mode to save your install, or use the floppy's and do a system recovery, some how.
Microsofts web page can tell you the recov details. There's a program that'll install the latest aspi stuff, after you install adaptec, so you don't have to pay for the latest versions of it, and its a lot faster.
This is the Aspi Layer updater, very usefull
BTW,
It's a known issue that most 0lder vers of adaptec will majorly mes up win2k, with their wierd drivers, I nearly got scared off win2k because of it. But Its easily remedied, now if only they had decent drivers for my soundcard for win2k.