BSOD caused by encoding section of win7 exp index?

Hi, upgraded a family members pc thats used for playing oldish games but is only a year or so old, have gone from on board graphics(radeon 4200hd) to a known working nvidia 6600gt that was fine in another machine.

I uninstalled all display drivers first and also ran a driver cleaner in safe mode, before installing the drivers from the nvidia site. The pc is also not overclocked.
When i tried to run the windows experience index it failed while running the decoding part(?) and fails at the same point every time(more info below).Apart from this all seems well, i havent tried any games or anything but it runs pcmark06 through.
Any help would be greatfully recieved. I have(i hope) attached the zip files usually needed in bsod posting.

Bsod info:0x00000116 (0x84D13510,0x8D150AA2,0x00000000,0x00000002)
nvlddmkm.sys- address 8D150AA2 base at 8D006000, datestamp 4f347a28

Win 7 32bit
Gigabyte ga-ma785gm-ud2h
Athlon X2 4800+ skt AM2
1gb ddr2 800(memory upgade in the post)
500w psu
Nvidia 6600gt (3D1)

 

I'd guess that the 6600GT has developed a problem or that the current PSU is not up to powering it properly; difficult to pinpoint without running a raft of tests though.

My debugger's currently hanging, I may need to reboot to try to find any further info, which is unlikely anyway. I'd try an older nVidia driver, WHQL preferred. Go through the cleaning/cooling process underlined above.

What PSU make/model do you have? Age of it?

Is the 6600GT still good back in the original machine it was pulled from?

 

Could well be the power supply it states winpower 400w, and looks about as cheap as they come and is also old.
With it running 3dmark06 no problem though i sort of ruled it out. The other machine has already been assimilated but i have a better power supply on its way for my own semi new build.
In the mean time ill try an older driver, big thanks for the help.

 

No worries, good luck