I just wrote a giant post on this and it apparently died somewhere.
Anyway, to recap in a few hundred less words:
the NX bit keeps a lot of software from working: Microsoft page on this is at:
http://support.microsoft.com/default.aspx?kbid=884130&product=windowsxpsp2

The Aspire 1700 series will run on Win2k; acer just doesn't support it, and the drivers they provide are pure XP. all the apsire hardware has Win2k drivers, they just aren't available from acer.

Um... the aspire also has a hyperthreading intel processor. Win2k doesn't support hyperthreading (it will run, just not with hyperthreading). get a AMD CPU and it's not an issue.

Xp is to Win2k what WinME was to Win98se.
Note I'm not saying XP is buggy, I'm just saying it sucks in comparison to Win2k.