ATI 5770 problem BSOD please help

Hi there... im kinda new to this forum so forgive me if i mess this up.

So here is my problem. just resently i got windows 7 64 bit for my computer. before that i ran windows vista 32 bit.

Everything was going fine up until i installed my drivers for my 5770... i boot up the computer after it tells me to re boot from installing the drivers. and as windows 7 is loading i get a 0x116 stop BSOD error... this only happens when i have the drivers installed. I can still run the computer in vista just fine.

here is what my computer is running

450 watt power suply. <-- i think may be the problem

8 gigs of ram <--- the power drainer i think. not sure tho. not to tec savy.

amd athlon 5200 64.

AMD mother bored.

sapphire 5770 HD vapor-X card.

now i know 32 bit for vista only can run 4gigs of ram and windows 7 64 bit can run more then 8... which is what i have... i dont know but it seems like its to much for my power suply to handle...

I hope someone can help me out... im completely lost at this point and dont know what to do...

thank you for your time.