mclaren lm, is outrageously powerful!

i cant start racing with addon cars. i can race w/ genric cars, but not with others.
and, i cant run mm2 with certain cars, such as the range rover vouge and nissan skyline by htqm team

aztually i got it to work now, i just right click and run as administrator.

mm2 worked fine. one day, it stopped working at the car select screen.

i got rid of all custom cars, it still stuck.
i reinstalled, it still got stuck.
HELP!!!

ps i have vista sp1 and an onboard intel graphics card.

i would make a buggatti, maserati, lotus elise, lotus exige, and a lotus evora.
ps i would like those 2 be made as well