Hello, I wish my first post here at macrumors was under more pleasant circumstances. But, be that as it may, I face the following situation. My 4 year old BTO 24" imac suffered a second GPU coronary failure yesterday. This machine was ordered with the nvidia 7600GT, 256MB VRAM. The original video card was replaced in July, 2008 by apple tech support under my extended APP coverage. Now, the same failure (same symptoms as before-herringbone artifacts appear on screen then system freeze) has occurred to the one they replaced. Strangely, the upper case did not feel hot when touched, so like before overheating can generally be ruled out as a culprit. My question, can anyone please offer me guidance from their own personal experience or knowledge on how to negotiate with apple support? I have a reservation for tomorrow with the genius bar and I would like to believe I have some leverage since this will make 3 GPUs in 4 years. thanks for reading and this is one great forum community, donbach p.s. I followed all the instructions at apple support including verbose logging and zapping PRAM to no avail. Only a white screen which forces me to press and hold the power button to shut down.