Computer Powers On and Off repeatedly on boot.

[Mr.Funsocks]

My PC has, in the last few months, started doing this thing that I never thought much of, but now seems to make it incapable of booting whatsoever. And for the life of me, I can't figure out what it might be, or a way to test it, barring buying a new part and replacing it to see if it works. And if I do that I'd rather know what I am doing first.

The problem basically is that when I push the power button, everything powers up (LEDs, all the fans, hard drives, DVD drive, etc.), then after 2-3 seconds, turns off. Then it powers up, then it turns off. And it continues going on and off every few seconds pretty much 'till I kill it by holding the power button down or switching off the PSU.

However, this isn't a consistent problem. The time it remains on during the cycles is variable, from half a second to 10 seconds. Sometimes, during one of the cycles, it powers everything up to max and just keeps it on 'till I kill it. Everything's going, but the system doesn't boot. No beeps, bloops, anything on the screen, no HD changes, nothing. And every once in a while... it actually boots up and works fine.

The system has basically always done this in a sense, and for some reason I thought it was normal. Ever since I built it, it would power up once, turn off, then turn back on and boot normally. I seem to remember reading somewhere that the case or motherboard had that as a feature, some sort of power on self test, but rereading the documentation I can't seem to find it. Never gave me any problems, didn't think much about it.

The problem also seems to have been progressive. The first few months I had the system it worked flawlessly. Then, it started doing several cycles of powering on and off before it would boot. Then at some point, the Windows 7 hybrid sleep mode just stopped working, the system wouldn't turn off no matter how long I left it. And just today, as I tried playing Civ 5 for the first time, the system cut out randomly twice, after about 30 minutes of playing. Subjectively, it also seems like the number of cycles has been getting longer each time, but I don't turn off my PC that often and haven't really counted the cycles.

I've tried disconnecting various parts and booting it, to no avail. And since I get no diagnostic feedback whatsoever from any part of the computer, I'm sort of at a loss of where to look.

System Specs (including everything I can think of):
Windows 7 Ultimate x64
600w PSU
GeForce GTS 250
EVGA P55 LE Motherboard
Intel Core i5-750 Lynnfield 2.66 GHz
80 GB and 1 TB hard drives
DVD Drive, wireless card, 2 monitors, wired mouse and kb

Links to the parts:
FSP Group FX600-GLN 600W ATX V2.2/EPS12V SLI Certified CrossFire Ready Active PFC Power Supply

Palit NE3TS25EFHD02 GeForce GTS 250 E-Green 1GB 256-bit GDDR3 PCI Express 2.0 x16

EVGA P55 LE 123-LF-E653-KR LGA1156 Intel P55 ATX Intel Motherboard

Patriot G Series ‘Sector 5’ Edition 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666)

Intel Core i5-750 Lynnfield 2.66GHz LGA 1156 95W Quad-Core

Western Digital Caviar Blue WD800JD 80GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive (system drive)

Seagate Barracuda 7200.12 ST31000528AS 1TB 7200 RPM SATA (storage drive)

Antec Three Hundred Illusion Black Steel ATX Mid Tower Computer Case
Rosewill RNX-G300LX IEEE 802.11b/g PCI Wireless Card
Sony Optiarc 24X DVD/CD Rewritable Drive Black SATA

 

[bjlockie]

1. Do a memory test (memtest.org).

 

[Mr.Funsocks]

So it did something new. Now instead of cycling endlessly or getting caught in the cycle, it'll only do a cycle or two, if any at all, then stay at the state of high use like it always does (all the fans on max, constantly trying to "read" the DVD drive, etc.), then slow back down to normal booting speed. And it'll try to boot. And it'll fail.

The first two times, I got the POST code 6C on the failure (handy little LED on the motherboard displays them) and no beeps. I can't find what that means anywhere (apparently the 6s are reserved for individual chipset manufacturers, and nowhere does it list them for this motherboard, the manual goes from 60 to 75). So I restarted it again to see what all codes it was giving out in the booting process. And this time it booted up, got further, and gave me an error I could actually diagnose! And it was bad. 85, which is apparently a display issue. I'm not getting anything to display on either of my monitors (right at the start it displays the system info like normal then nothing), and that seems to point to the graphics card. And I reeeeally would rather not replace it if I can help it. Also, I got two beeps for some reason, which don't appear to mean anything...

So I tried a spamming delete to get into the BIOS setup, and I got an 87 and two beeps. 87 is apparently it trying to enter BIOS setup. So it fails either when initializing graphics, but gets past that if I'm trying to enter setup? 85 pops up very briefly before 87 says hi.

The POST code list if anyone was so curious: http://mxdtr.com/p55-motherboard-code-codes-error-messages-system-boot-up/

 

[Mr.Funsocks]

This thing just gets weirder... I started disconnecting/reconnecting various things (starting with RAM), and getting the same error. I disconnected USB devices and it did the same as before, gave me the two annoying beeps with an 85, then... continued to boot. So I reconnected my mouse and keyboard, and we'll see how long this lasts... Maybe it doesn't like my printer?

 

[KGB]

As a troubleshooting step try disconnecting the power switch connector from the MB.
Then, try MOMENTARILY shorting the MB header pins with a screwdriver blade and see if the system stays on.

 

[Triglet]

By chance have a spare graphics card to throw in there and see if you get the same thing? I just had a similar issue with my gf's pc -- the 7800GTX went bad. Just kept getting progressively worse until it wouldn't boot at all. Cheapo graphics card fixed it.

Maybe try booting without the graphics card and see what happens.

GL!

 

[Mr.Funsocks]

I tentatively think I've fixed it, was a bum PSU. I had tried disconnecting everything possible, including the graphics card, and was getting the same thing, so it didn't appear to be the card, luckily. Ordered a new PSU, just put it in, booted up smoothly the first time. Gonna test Civ V to see if it fails now, god knows why it's Civ V that decided to fail on me.