Computer turns on but doesn't boot

[Blarg]

So earlier today my computer restarted for no reason just like how it would if the power flickered but there was no power problem. When it started up again there was no power to the monitor (yellow light rather than a blue/green one) and both my mouse and keyboard (both USB) don't have any lights that work so I'm guessing no power is getting to them.

I found similar problems online that were fixed by resetting the CMOS or something of the sort. Basically I unplugged the computer and held the power button in for over a minute and tried to turn the power back on. I also removed the motherboard battery for half an hour and then put it back and tried to power back on. Neither worked.

I've also tried removing the RAM and restarting which is supposed to do something but it didn't work. I can't see any blown capacitors either.

The fact that the computer restarted on its own just before this problem makes me think it's a PSU but my graphics card also seems to be acting strange now, but that could just be connected to the power issue.

When I am trying to restart the computer over and over for the most part the graphics cards fan won't start (though it sometimes moves a tiny bit when I press the power button on the back on or off). If I flick the power button on the back off and then on right away the graphics fan does turn on but it's being very loud and seemingly going very fast but even then the computer won't start.

[Aldon]

Tough one, could be either a motherboard or PSU issue. If you happen to have a spare PSU to swap out, give that a shot. If you have a multimeter I would unplug the 24-pin ATX connection and start testing those pins for voltage to see if they are running what they're rated for.

Another way to test is to remove your video card entirely and run off of motherboard graphics, Remove any peripherals you dont NEED to boot (wireless cards, extra hard drives, DVD drives, etc etc etc) and see if you can get it to boot. If it will boot after removing the periphs, it is likely an issue of the power supply not being able to supply the required wattage.

[Blarg]

I removed everything one by one and nothing got it to boot. Removing the vid card just put a message on my monitor to check video cable.

[Deuce]

Do your case fans turn on at startup?

Also, if you have the side panel off of your case can you see any lights turn on located on the motherboard and do they turn off after a few seconds?

[Blarg]

Case fans turn on, hard drive feels like it's on. Graphics card fan doesn't turn on unless I flick the PSU power switch off then on (even when I do that it doesn't happen every time) in which case it turns on and is really noisy/fast. (BTW is it normal for a graphics card fan to turn on during startup or does it wait for something where fancy graphics are needed to be made before it turns on.)

I don't see any lights on the motherboard but I don't think there is anything on the MB that would light up anyway and I don't remember ever seeing lights on the MB.

[Aldon]

Alright, if all your case fans turn on and your video card fans turn on during the PSU's power on, then I'm going to guess it's your motherboard.

When your power went out, your PSU probably took a hit, but it sounds like your motherboard took a harder hit.

[xopher]

I've seen a bad GPU cause this problem before as well. Do you have a spare GPU you could try or maybe an onboard one?

[Deuce]

GPU fan turning on at startup is normal. They do it as part of their bootup procedure, but the fans should only spin quickly for a few seconds. If fan speed is faster than normal under minimal load and persistent then it is likely a dead video card.

I'd agree with xopher to see if a GPU swap works next.

Also if any of your fans connected to the MB turn on but stay at a high speed for a long time then it is likely the MB got shorted.

Edit: I should specify that my fan comment only refers to those that have speed controllers connected. If not they'll run at full speed the entire time they're on.

[Blarg]

Alright, if all your case fans turn on and your video card fans turn on during the PSU's power on, then I'm going to guess it's your motherboard.

When your power went out, your PSU probably took a hit, but it sounds like your motherboard took a harder hit.

To clarify the power didn't go out but my computer did that super fast reset which is identical to how it does when the power does flicker out for a microsecond during a storm. The lights in my room and other computers did not reset.

Also, my video card fan only turns on super fast (and stays super fast) when I flick the PSU power button off then on very quickly and only then some of the time that happens. For the most part powering on the computer the standard way has the GPU fan not turn on at all.

I have no spare video card and in an earlier post removing the vid card didn't change anything and gave me the message to 'check video cable'. Is it possible I don't have onboard graphics?

[Deuce]

To clarify the power didn't go out but my computer did that super fast reset which is identical to how it does when the power does flicker out for a microsecond during a storm. The lights in my room and other computers did not reset.

Also, my video card fan only turns on super fast (and stays super fast) when I flick the PSU power button off then on very quickly and only then some of the time that happens. For the most part powering on the computer the standard way has the GPU fan not turn on at all.

I have no spare video card and in an earlier post removing the vid card didn't change anything and gave me the message to 'check video cable'. Is it possible I don't have onboard graphics?

Ok, if the GPU fans are having that issue then it's starting to make more sense that the card is fried, but that won't rule out the MB and PSU from being damaged either.

If you can, take the GPU out and swap it for another card in one of your other computers. Then try turning on that computer and see if it works. If everything turns on, but you don't get a video signal or the fans don't turn on normally then I'd say the card is dead. If it works fine and you get an image we can rule it out as the problem.

[Blarg]

If it was just the GPU why would my keyboard and mouse not get signals either. The other computers are really old so I can't swap with them.

I did go to a computer store to look for a PSU to test it but they didn't have PCI-E connectors with 2 6pins (which I need). They only had 1 6pin but when I look online most of them have 2 6pins so I don't know what is going on with these stores.

They do free diagnostics so I'll probably take it in and find out what is fucked.

Thanks for helping everyone.

[xopher]

GPU fault at boot can send a signal to the motherboard that says "don't even try anything else, we're done here."

Really leaning at GPU here.

[Blarg]

GPU fault at boot can send a signal to the motherboard that says "don't even try anything else, we're done here."

Really leaning at GPU here.

Is it possible that I don't have onboard graphics because even when I removed the GPU the keyboard/mouse/monitor didn't light up.

[xopher]

what motherboard do you have

[Blarg]

P43 Neo which when I google it (http://www.expertreviews.co.uk/mothe...specifications) says that it does not have integrated graphics.

Are there any brand PSU's / motherboards that I should avoid and which graphics card company is preferred now. I won't get anything super new even if I do upgrade though so is there a good budget card that is still respectable.

[Aldon]

P43 Neo which when I google it (http://www.expertreviews.co.uk/mothe...specifications)

Well shit, it really DOESNT have any onboard graphics... That's.... rare... makes it a lot harder to diagnose in the absence of another spare video card.

[Buffy]

P43 Neo which when I google it (http://www.expertreviews.co.uk/mothe...specifications) says that it does not have integrated graphics.

Are there any brand PSU's / motherboards that I should avoid and which graphics card company is preferred now. I won't get anything super new even if I do upgrade though so is there a good budget card that is still respectable.

Seems to be a little bit of a swing back to Nvidia going on atm....not huge, but an undercurrent.

[xopher]

You don't have any friends that would let you borrow a gpu for 5 minutes?

[Blarg]

It was the motherboard for sure, and possibly the graphics card but that needs to be tested after a new mobo is in. New mobo also means that my old cpu won't work so I need a new one of those and new ram that is ddr3

[Deadgye]

Time to get a new computer.