One of my ATI Radeon HD 2600 XT 256MB graphics cards is not working on my early 2008 2 x 2.8 Quad-core mac pro. Wondering if I should call Apple or take it down to the genius bar (only 5 min. from house)? Anything I should check to make sure it's dead? The thing is I haven't used this card since the first couple weeks. I starting using the other card because I felt this one would hiccup (blink?) occasionally. I wasn't sure if it was the new LCD or the card at the time, never happened hooked up to the 2nd & current card I'm using. Now, I hook up a monitor to it and I get nothing. I did notice some red light through the fan hole from the back of the Mac Pro recently, more than usual. Not sure it that was related. However, I recently tried the card and nothing, either side. System profiler shows the AT Radeon HD 2600 XT and the Dell LCD I'm using on Slot 2. Slot 1 shows: Type: Display Bus: PCIe Slot: Slot-1 PCIe Lane Width: x16 Vendor: ATI (0x1002) Device ID: 0x9580 Revision ID: 0x0000 Kernel Extension Info: No Kext Loaded Displays: Display Connector: Any thoughts?