Power Mac G5 not starting

Hey folks! I have a Power Mac G5 quad core 2.5 that isn't starting up. I'll give you all the info I have so you can help diagnose the problem.

I recieved this computer second hand and it worked great. However, about two years ago it would atart shutting down and the OVERTEMP led would come on. I started running the machine in "reduced" mode, and while not ideal, i was able to at least use thw machine. I researched and found out about the issues with the liquid cooling systems and the heat.

Last Friday, and computer shut itself to sleep while i was using it, with the OVERTEMP led again lit. I would not wake up, so I shut it down. Now, when I attempt to restart it, the power goes on, there's no chime, and after about three second the CHECKSTOP led lights, quickly followed by the OVERTEMP led.

I pulled out the LCS, and there was no sign of leakage (I saw pictures of some people who had rice or salt like deposits all over their logic boards. Mine was fine.) I took the LCS apart and flushed the heck out of it with hot water. There was sediment in the radiator, and a lot of clogging in the filters right behind the processors. I cleaned it all out, gave it new coolant, clean hoses, and fresh thermal paste. I put everything back together, but I got the same result at startup.

I also changed the PRAM battery and reset the SMU. Still the same thing.

So that's where I'm at. Does anyone have any ideas, because at this point I'm open to anything. I don't have the money to replace this machine, and a lot of my life is on here, especially the articles my girlfriend writes for the local paper. We don't have a laptop, so this is the only way she can do her writing.