Desktop won't post!

[kuronosan]

Mobo: GB n650i DS4
RAM: Corsair XMS2 Dual-Channel 2x1GB, OCZ 2x1GB Performance Ed
VGA: nvidia 8600GTS, PCI-Ex8

Stock cooler, 600W PSU.

It was working fine last night, and when I shut it down nothing showed any signs of problems. I go to turn it on this morning and it's stuck in powering up mode. No POST beep, nothing. I took out the RAM and the VGA to see if I'd even get an error beep. No go. All the fans are working, all the drives are spinning, just no POST. I need this computer working so that I can finish my reports!!!

[kuronosan]

Okay, new symptom: Now it turns on, begins to boot (I know this because my printer starts to POST when it boots) and then shuts off after a distorted POST beep.

[Senoska]

Shooting in the dark: Bad mb?

Why would the post be distorted?

[kuronosan]

I don't know, the only other thing I could think of is the PSU being bad or overloaded (not a large enough PSU). It turned on briefly, started to POST, then shut off on its own. Now it's back to staying on again.

[Olo401]

Sounds like a power issue. Check the motherboard and CPU power connectors to make sure they're firmly connected, then check for frayed or burned-thru wires. If you don't find anything look for fried capacitors on the motherboard (tho you would probably smell those).

Also, need to know what the make/model and specs of the PSU are. You'll find all that on the UL sticker.

[kuronosan]

OCZ600SXS, P/N PPA6000118, S/N: S7281000769

No burning smell, I looked for burnt capacitors or anything out of the ordinary.

Now it's doing that quick start-up, turn-off thing. I hear a buzz for about a half second and then it just shuts off.

edit: Okay, now it's just sitting there again, doing nothing. No POST, all the fans are turning.

[Olo401]

Yeah was afraid of that.. that sounds like the PSU's just failed.

To be certain, if you have a spare PSU handy hook it up and see if the machine gets to POST.

[kuronosan]

Since this was the first LGA775 machine I built, I don't have any other PSU that will attach to it. I'm going to reset the CMOS first to see if that fixes it and then I may go out and just buy a new PSU. If that doesn't fix it, I'm going to be quite pissed. I have two lab reports due this week and my computer acts as the server for my printer. -_-

edit: Reset CMOS, nothing. Unplugged both HDD, DVD-R, and the VGA. Nothing. Just turns on and no beeps. All fans moving, lights on, etc. No POST.

[kuronosan]

Okay, so I took the CPU out to see if it was a power issue and the processor looks fine... no damage... no seemingly melted parts... I put the CPU back in without the fan to see if it would get hot...

It still won't POST or do anything... so I've narrowed it down to either the motherboard or the CPU.

I have no way of testing either theory without buying one or the other... WTF do I do?

[Bockage]

I had almost the exact issue earlier this year. I went out and got a PSU tester and determined it was my mobo.
Something like this will do the trick. It'll let you know how screwed you are for about $20.
Ultra ULT31553 20-/24-Pin Power Supply Tester - RadioShack.com

[Caiyuo]

This is probably going to sound stupid, but are you using 4GB of RAM in 32-bit? I'm guessing from OP that you have 4GB in total between 4 separate 1GB sticks, yes?

[kuronosan]

Yes, and no - this is a 64-bit system. It was working fine last night when I shut it down. When I booted it up this morning, it just turned on and didn't POST.

I took all the parts out and turned it on, and it still doesn't POST. Doesn't even POST to say "hey no fucking CPU or RAM wtf". It just loads up and gives power to the fans. CPU is cold to the touch.

[Rementoire]

If you've got more than one stick of RAM then try booting with each, one at a time. Oh, and I now see that you're using 2 different makes of RAM which could easily be your problem.

Also, did you originally apply thermal paste and then reapply once you'd reinstalled the processor? I have to ask because I'm not sure how familiar you are and I've seen people not use the stuff at all.

*EDIT*

Read your most recent post. Does it beep when you power it on without the RAM?

[Caiyuo]

Balls. No clue, my best guess being that your reports are obviously more committed to not being finished than you thought.

[kuronosan]

Okay, so I went and bought a new motherboard. Same issue, won't post. Sometimes fans come on and one time the CPU fan lagged in turning on. Should I assume the worst that I'll need a new CPU or should I assume that the PSU is going dead?

I've unplugged everything and the ram and left just the CPU in there and it will turn on but still won't post.

[SephYuyX]

Wait. You said the CPU is cool to the touch after turning it on?
Thats your biggest tip.

CPUs become hot, whether the PC POSTs or not, but depending on how fast it heats up is a way to see whats broken.

Three things factor in to that, PSU, MB, and CPU. PSU was already brought up, and that should have been the first thing you replaced, not the MB. When it's a shoddy MB/CPU the CPU becomes blazing hot, fast. This is one diagnostic test, albeit a 'primative' one. If you stick your finger on the CPU, turn it on, and you singe your finger in less than a few seconds, either your MB or CPU is shot.

Why is your CPU cold then? Because your PSU isnt giving it enough power. PSUs can seem like theyre working (fans turn on, pc acts like it wants to run, etc), but it just means theyre about to die.

Replace your PSU, 95% chance that's your problem, and in the future, always start at the PSU first (after reseating everything).

[kuronosan]

I wish you were around earlier, Seph... it would have saved me a world of trouble. I thought a cool CPU meant dead CPU or dead connectors.

But yea, before I replaced everything I put my finger on the CPU, booted up the machine, and ... nothing. Fans whirled on, case came to life, but CPU was extremely cool to the touch.

[SephYuyX]

The CPU should still get hot regardless if it works or not (after all thats a lot of heat being transfered to it).

The times when the PSU works, and the CPU is still cold, means the MB is completly fried, and theres no juice reaching the CPU at all.

If the CPU gets super hot fast, more times it's the MB that's having issues, and the CPU is fine.

It's kind of hard to tell if the CPU is dead or not (by using touch and visuals), but it's easy to tell via POST/beeps.


Using this method of testing is extremly risky for numerous reasons, and not many know about it. The only reason I know of it is I had a similar issue, and when I called GIGABYTE about it, they told me to touch my CPU while turning the PC on, and I singed my finger real good within 2 seconds, but that meant my MB was DOA. This was many moons ago, and I guess they wernt thinking about consumer saftey lol..

[kuronosan]

Well this new motherboard I have has an internal diagnostic system that tells you. I got the EVGA 750i. All lights are green and everything seems to be fine, but the LEDs on the inside flicker slightly and make a slight clicking noise.

No HDD activity, no spinning, the fans all light up gorgeously... and yet no POST beeps or anything. I would think if the CPU was the problem it should still get hot shouldn't it?

I really think the PSU is the problem at this point.

[Ratatapa]

when i built a PC at work it used DDR3 memory the board had 6 memory slots, so i wanted to do a test and put 5 memory only.

The PC booted but jammed at the "Motherboard screen" since DDR 3 need 3 bars to run etc

And ya the PC didnt beep there, could be same thing with DDR2?