Graphical Issues after re-build

Apologies if this is in the wrong thread, used to be a windows 64 thread.
Hoping you can help, I have a Nvidia based 6800GT AGP graphics card, I have
recently changed my motherboard from a Gigabyte k8ns to a asrock 939dual (the
one with an AGP and a PCIE slot, I also run a dual boot OS Windows XP Home
and Windows X64 Pro, Where as the gigabyte board had no issues running
certain games under the 64bit, I am experiencing graphical anomilies on the
ASROCK board, eg Tomb Raider Legend, has no menu interface in Win 64 yet runs
okay on the 32 bit home version, I have tried updated drivers, Board drivers
etc etc and still no go, Other games, Quake 4, will lock up on the 64 and not
on the 32. Any Ideas
Martin Glenn