Hello everyone, been forever since I have been on here. Pulled my ole' G5 out of storage after a few years today and wanted to play around with it. 2 of the ram sticks went bad, popped in 2 different ones and had my whole 8GB again. Then the fans were running sooooo loud, much louder than I remembered. So I tore it down, replaced the thermal paste on both CPUs (it was all dried out), and buttoned everything back up. Now it wont POST at all. I turn it on, it runs for like 5 seconds then shuts off. Reseated the cpus into the 2 sockets again, and issue persists. Not sure what could have gone wrong at this point. Or what else to try quite honestly, as I feel that it would work right now or its busted. (Maybe I bent a pin? Cant tell.) Has anyone been here and turned out it was something silly? Or is time to gut it and do a PC build in it (yuk) 
, pretty sad as before I took it apart today, it was running so well, aside from the jet engine taking off. iStat was showing 60C at idle on cpu A and 40C at idle on CPU B with fans at 3000 RPM. So I figured might as well replace the 15 year old paste. I used Tuniq TX-4 which I have used on several gaming PC builds as of late, and it seems to keep temps nice, even with overclocking, so figured it was a good candidate for the steamy G5s. No visible signs of coolant leaking either. Granted, this is the first time I have opened the case in probably 5 years, but figured their would be coolant residue or rust visible. Thanks for any input!
EDIT: Also wanted to mention, that when re-torquing the 4 screws that hold the cpu to the water block, two of them on one of the cpus, would barely tighten, and you can see alot of threads showing, but even then, I doubt this would be a no POST situation. I tried to tighten it all the way but it wouldnt budge even with some big screw drivers, which is insane because this is a pc tool kit type job.
, pretty sad as before I took it apart today, it was running so well, aside from the jet engine taking off. iStat was showing 60C at idle on cpu A and 40C at idle on CPU B with fans at 3000 RPM. So I figured might as well replace the 15 year old paste. I used Tuniq TX-4 which I have used on several gaming PC builds as of late, and it seems to keep temps nice, even with overclocking, so figured it was a good candidate for the steamy G5s. No visible signs of coolant leaking either. Granted, this is the first time I have opened the case in probably 5 years, but figured their would be coolant residue or rust visible. Thanks for any input!EDIT: Also wanted to mention, that when re-torquing the 4 screws that hold the cpu to the water block, two of them on one of the cpus, would barely tighten, and you can see alot of threads showing, but even then, I doubt this would be a no POST situation. I tried to tighten it all the way but it wouldnt budge even with some big screw drivers, which is insane because this is a pc tool kit type job.