can not un-install software!?

I am trying to un-install a microsoft simulator game-
and after i give permission to continue the un-installing, control panel begins to un-install, but stops
just as quick as it started! i tried again and again.
the game is over 3 giga-bytes, and i need the space.
if anyone has a answer for my problem, or if anyone knows a different route i could take other than control-panel un-installation please help! i am using windows vista-thank you!-chris