need help installing my graphics driver in windows vista via boot camp

New to mac so first time on forum as well.

Love the Mac but i also want to get on some old games. C&C The First Decade mainly.

I am currently using below.

Mac mini Mid 2011 processor 2.5 GHz Intel Core it

Memory 4 GB 1333 Mhz DDR3

Graphics AMD Radeon HD 6630M 256 MB

Software Mac OS X Lion 10.7.5

Installing windows vista home premium 32 bit

I have installed windows vista home premium using boot camp assistant and downloaded the windows drivers as well. After i have installed windows i installed boot camp using my Mac OS X snow leopard which installed boot camp 3 or 3.1 i believe and i eventually got apple updates for 3.2 which is what i am now runnning on vista. I had trouble getting my sound to play through my speakers at first but eventually got them working and now it is my graphics driver that i cannot seem to get working. In vista(I also downloaded service pack 1 and 2) when i go to control panel and check out my device control it shows a yellow exclamation point next to the adapter. I guess i need help in getting my graphics installed correctly on my windows. Is there something i should take off to install the correct driver? Or do i just need the correct driver download? If i have the correct driver how do i upload it onto my windows side in the device control.

When i try to run c&c generals/zero hour i get a directx 8.1 error, red alert 2 is black but i can hear. i know these games can work i installed the graphics correctly the first time when i did not have sound as this is my second time installing windows so the game did load when i did not have sound.

Advise?

I was thinking about saying forget this i can't waste hours of my time anymore but i have to be close to getting everything working if i had graphics before and no sound but sound this time and no graphics. I was also thinking about just buying windows 7 home premium sp1 64bit system builder dvd off amazon and reinstalling windows using windows 7 but i want to make sure i can play these games before i spend the money. I thought my mini couldn't support windows vista and if it did only boot camp 4? how am i getting this far to get things to work?

What is the driver i need to install to get these games working? What do I need to do or what am I missing???

Do i need to install a different boot camp off apple and find a driver that will get mine to work in vista?

Any and all responses will be greatly appreciated i have been at this everyday for hours.