Display has - Split screen, pinstripe lines & Black Screen!

It seems that when the Intel graphics card is in use all is ok, but when the AMD switches on the fans kick on and the MBP starts to get really hot, then the video fails with various issues ranging from a split screen, pinstripe lines, black screen, etc. All I can do is power off.

Then, even after cooling down, it might take overnight before I can power it back on and have a working computer.

Resetting SMC, PRAM, NVRAM, etc. is of no help. I can't get it to go into safe mode at all. I can't even get it to boot off the OSx install disk until I wait 8 - 12 hours. I swapped hard drives and reseatted the RAM, but my diagnostics say all is ok.

I also took it to the genius bar and their diagnostics show no issues as well, but the tech says it is a failing video card and Apple will replace it for $310.