Ok sorry incase i missed this but what manufacturer is the card made by?
Depending on the manufacturer your RMA doesnt even need to be with OCUK
you can just send the card back to gigabyte/BFG or whomever else it may be, granted you may need to wait longer.
did you keep the origanel ram pads on the cooler that was there to sit on top of the ram chips and did you leave the gunk on the core section they put on.
if so slap the stock cooler on, try the card with the stock cooler, infact if needs be get a spare hard drive, install a fresh copy of windows on it with fresh driviers and see what that does.
its a long shot but when cards overheat now you get failure to comunicate with the driver errors so in theory it may be possible that the card did overheat but corrupted the drivers? i know its a very long shot but as you are worrying about, you have a £200 card at stake so this is a small task in comparrison.
And for gods sake if it all fails you have to try and RMA it whats the worsed that can happen they send a borked card back with denyal of RMA your down an extra tenner and need a new card as apposed to the up side wich is they could complete the RMA and you get a shiny new card and saying to yourself damn im glad i listend to those peeps on the forum.
