After 5 years it was bound to happen, I've experienced my first non-obvious hardware failure.
I have very little experience with diagnosing these so any help would be greatly appreciated.
During use my computer immediately turned off and would not start. Upon pressing either power or the memOK button on my ASUS P8P67 PRO motherboard, the CPU LED and BOOT DEVICE LED would both light for a moment, and the CPU and GPU fans would just begin to spin, before immediately stopping after about half a second. Further attempts to power on yield no response until power is cut and then restored. As long as power is on the motherboard power LED will stay on green, regardless of what happens.
I have tried clearing CMOS, reseating all connections, testing one RAM stick at a time, removing both sound card and graphics card, and removing all but the two motherboard power connectors, with no change in result.
I have visually inspected everything and can see no broken components and cannot smell any electrical smoke.
I'm hoping it's the power supply, which would be the easiest component to replace, I'm wondering what other TR forumites might think the problem is. It seems to me that it's either the CPU (somehow so messed up it is interfering with post before it even really begins), the motherboard (not finishing a post attempt due to being broken), or the power supply (broken in a manner which prevents it delivering any significant amount of power).
I'll be testing with a difference power supply tomorrow morning, any help would be greatly appreciated, thank you for your time.
firstname.lastname@example.org, P8P67 PRO, 8GiB DDR3@1.6ghz, GTX 570, Xonar DX, Intel 510 120GB, Deskstar 7k3000 3TB, Corsair 600T, OCZ Fatal1ty 750W.