you may need to re-install windows,
you could do this without a format (just delete the windows dir or even just put a new hardrive in,
and set in your bios to boot from cd,
usualy is a boot order setting there.
iv'e had a similar problem before with an arcade vga,got it 2nd hand,
The driver disc i got was damaged and when i tried to install
with a downloaded driver it just wouldnt work,
it may be because there so many versions of the card,
but now i mainly use dos.
I have 2 arcade vga's one is a ati 9000 based, ( i had problems with driver in windows but worked fine under dos)
the other is a newer 9200 based which always worked fine in windows,
give andy at ultimarc an email, he's a good bloke,im sure he'll help you out if he can.