Did you have VIA 4in1's installed before the upgrade? I ask because Abit reccommends against installing 4in1's due to the native suport for these borads in XP. I have a KG7-lite and have never installed any motherboard drivers. That said, maybe you should consider a backup and reformat. I ended up having a couple issues when I snagged my 9500Pro and the reformat fixed things. It is a bit of a pain in the ***, but short of updating drivers (which you have already tried), I'm not sure.
Have you tried completey uninstalling the card from your sytem and installing it again?
Cheers
---------------------------------------------
Abit KG7-lite
Athlon XP 2000+ T-Bred
Vantec Aeroflow VA4-C7040
2x256 MB Crucial PC2100 DDR
Enermax EG365P-VE FMA 350W PS
Maxtor 40 Gig D740X-6L 7200
LG GCE-8320 32X CD-RW
BBA ATI Radeon 9500 Pro 128MB
LG 995FT plus 19" monitor
Soundblaster Live! Value
3Com 900b 10/100 ethernet
Windows XP Home