Windows XP install Dell Dimension 4100 i815 chipset lock up
Faced with the same problem regarding the fate of a Diamond card I had installed, I found the web site for the company that had bought out Diamond and retired the line. Although they didn't have an XP driver, or for that matter any NT driver at all, for my specific "Diamond Something" card, they did have an alternate driver for a "Diamond Somethingelse" card that worked fine for XPPro.
I know there's a well-known issue with Dell Dimension 8400's displaying an alert that video cards requiring more than 75W require an extra fan be installed. And I know that more often...
If OP is emotionally attached to the Alliance card, a google might turn up who bought them out and-or the possibility of alternate, probably S3 chip, drivers that would work with his card-XP.
My Diamond card was an old one I installed in an L733r vice the on-board video. Machine has been sold, but card still works fine for the new owner with XP thru SP2. -- OJ III Email to Yahoo address may be burned before reading. Lower and crunch the sig and you'll net me at comcast.
Dimension 8400, video cards, and "fan alert
alt.sys.dell talk from Newsgroups.