My Mac Pro no longer turns on after trying to perform the recent EFI firmware update. After installing it, the machine powered off. I turned it back on, and during boot, it abruptly turned off again. After this point I haven't been able to get it back on at all - no power light, no fans spinning up, nothing! I called Apple support and did the following: 1. Tried another power cable 2. Tried another outlet 3. Tested the same outlet with another device 4. Tried resetting the SMC by unplugging power cable and holding in power button for 20 seconds 5. Opened up the case and made sure graphics card and memory were seated properly. I have a genius bar appointment scheduled for Wednesday, but was wondering if there's anything else I can try in the meantime to avoid hauling this huge machine into the mall.... Thanks!