Vista - RC1 game issues

this could be due to the lack of nvidia drivers, but i doubt it...

2 games aint running right.
TMN (trackmania nations) - installs and runs to the config menu fine.
try to run the actual game and nothing happens.
UT2004 - wont even autorun (and i cant manually run setup.exe either).
installed fine last time i used the disc - 1wk ago installing it on linux.

i've heard of issues with pre-RC2 and gaming - is this typical of those
problems? if so, time to find an RC2 build if not - any ideas?

tim