Hi, I have an ailing Mac Pro 1,1 (firmware updated to 1,2 and running 10.7) - rock solid every day since purchase from new but yesterday I had an out-of-the-blue kernel panic and on restart I just got a stripy green screen. Next restart it got stuck re-chiming over and over and was unresponsive to any key commands. So, I opened it up and noticed the CPU B red led on the logic board was lit up. I went through all the reset options I could find online (removing power source, removing and reinstalling battery etc) but nothing worked. I tested each of the DIMMs and they seemed ok. After removing the gpu (Radeon 5770) and powering it up with nothing else connected (just the power cable) it didn't get stuck, the red light went out and all seemed well - so I figured it must be the gpu that died. To test this I installed the old gpu that came with it when new (X1900XT) and it now starts up but I'm getting random issues after a few minutes - kernel panics; restarts; spinning wheel; and sometimes it just goes blank with both the CPUA and CPUB led lights illuminated on the logic board. (When it is running I've pressed the LED diagnostic test button and the LEDs light up as they should according to the official service manual.) If I don't open any apps (only tried Mail so far) it lasts longer before something knocks it over and I even managed to copy off some files to a usb stick, but it's clearly not happy. I ordered a replacement 5770 but it's probably fair to assume something else might be the problem. Ok, the old X1900XT in it at the moment was on its last legs before I swapped it out for the 5770 but it didn't make the mac unreliable (just graphic glitches from what I recall). I did a cmd-R reboot at one point and checked the disk and there were no issues there. It's probably just going to be a case of replacing things to narrow the field (upgraded cpus will be next after the gpu) but just wondering if anyone has any pointers for me based on this report? Thanks in advance.