1 year ago my self-build shut down abruptly and wouldn't turn on. Spent ages trying to fix, no luck.
Just replaced PSU, motherboard and got a new case.
Put everything together, and it still doesn't boot. The fans nudge a tiny bit sometimes when the power button is pressed and the motherboard light is on, but it doesn't boot or get the fans spinning, same as before.
Can faulty RAM or GPU cause this (I have kept these components from my previous build). How can I diagnose what is preventing it from turning on?
Asus P5QL Pro
nvidia GTS 250
corsair TX 650 V2
2 x 2GB HyperX ddr2 1066 kingston memory
Those components wouldn't prevent the computer from booting to at least the fan check stage. As you have replaced the psu, and motherboard, I would say that your CPU has been destroyed. Maybe just try to reseat it, or try to find a bent or missing pin, but as you have the QX9650, I'd imagine you overclocked that pretty hard. Could have just reached the end of it's life at whatever voltage you had it at.
Your processor is not on the asus cpu support list. It does list the Core 2 Quad Q9650(rev.E0,3.00GHz,1333FSB,L2:12MB) but not the QX series. Is it one of the Compatible with Intel® 05B/05A/06 processors? Have you tried a bios update? At least 803 for cpu or 903 for better memory compatibility. Faulty memory can cause this issue also. Have you tried it with a single stick in the correct slot? Try one at a time to see if it boots. What is the exact memory modules you are using? Sorry, gotta ask - did you remember to connect the other 4 pin atx connector to the mobo?
I wouldn't think that a high-clocked and unlocked version of the Q9650 wouldn't be supported, when the regular edition is. I had the Q9550 for 3 years, and I ran that thing at 1.4v and 3.8ghz all day long. 'upgraded' to a fx-4100, and what do ya know...no difference.
Anyway I had some mild diagnostic success!
I removed everything except PSU and CPU and all the fans started and it beeped indicating no RAM.
Added ram, got beeps indicating no GPU. Added everything except GPU first, still boots all fans and hard drive.
As soon as I attach the GPU, nothing starts, no fans or beeps.