I think i castrated my card...

For some reason my card hasnt been fullfilling its usual potential. It started when I wass playin C&C3 (in Vista Home Premium) and wanted some extra frames, so I downloaded an OEM media center disc (got official MC) and installed it. It installed but half my computer was unrecognized, so i went back to vista, installing it the same way as i had done before.

Only difference was, when i went to play C&C3 the framerate was chopped in half. Same with Company of Heroes. So I reinstalled vista again, thinking i mighta installed windows badly. Same problem. Tried about 5 different drivers. Same problem. Tried changing clock speeds of my gpu but wasnt that. My computer also recognizes all my ram and cpus. Tried scanning for virusses I got desperate so i wipped out my recovery discs from acer (filled with bloat) and tried that. Alas, the problem persisted. And now i come to you guys, and wonder if iv partially fried my card somehow?

I did slightly overclock my card, but this computer isnt even 6months old and I would balance out the overclock with a bog ol underclock for day-to-day use. Even though I reinstalled windows I always kept my D partition untouched as its my storage space. Maybe something with that?

HELP!!!

 

Vista optimization maybe? That is a weird problem.