Failed graphics card?

I purchased a used imac with 3.06 GHZ, 750 GB HD and 4 GB of RAM.

Within 26 days of purchase, the screen froze, flickered and now will not boot up. I have run the hardware test and it shows that the hardware is working properly, but I am concerned that it may be the graphics card, which is known to be problematic in this imac.

I have reset the PRAM and have attempted to boot and perform a software check by holding down "C" when booting, but with no success.

I have heard that the graphics card in this imac (Nvidea 8800) has had lots of problems and has an average life of 2 years. In at least some cases, Apple has agreed to replace them because of the high failure rate.

Any suggestions? I am heading to the genius bar today to see if they can help.

When I boot, I see the apple logo, the wheel and then the screen