Computer won't turn on....then turns on by itself!

[biomanz]

Lately my desktop had some problems turning on - first nothing happens on the first power button press then boots on the second, then soon after needed to press it 3x before powering on. Well just now, after spending an hour double-checking and reconnecting the cables and refitting a used battery onto the mobo, it still wouldn't power on. About 5 sec after my last press, the pc just turned on....by itself..without me touching it.

Could it be the cmos battery on the mobo that needs replacing?

I noticed two "towers" (those cylinder heads w/ a cross on top) on the bottom of the RAM slots that are very slighty bulged on top. Not very obvious but not perfectly flat like the rest.

Once the PC turned on, it said "cmos error" then "press f1 to continue" which I did and is now working just fine.

Can it still be the PSU since it's now up and running?

My guess is something happened to the 2 mobo "cylinders" that's obstructing the initial power sequence or w/e. I'm afraid to shut down the PC now and am about to order an external hdd to back up my main drive (the others could plug into any pc and "work" right?).

Any help would be appreciated.

 

[TheKub]

Its hard to say with certainly but those 'Towers' are capacitors and typically when there is bulging it means the are or will soon be going bad. The CMOS battery will not affect your PCs ability to boot, though if its bad you will get the cmos error message each time but the machine will still work.

Its always a good idea to have a backup but given your description your hard drive does not appear to be in danger. Though you will be needing a replacement motherboard soon.

 

[biomanz]

Ok I found this tidbit of info:

"Finally, your power supply has a series of capacitors that store electricity. This lets you power up your computer without using a mechanical switch. When you press your computer's power button, the capacitor discharges a 5.5-volt current, telling the power supply to turn on. This in turn provides power to your motherboard, and your computer begins the process of booting up."

Now it seems to be a faulty PSU I have now. But I tore open the PSU and couldn't find any bulged/leaking capacitors (I know it voids the warranty). But if it's indeed the PSU, wouldn't it show more signs of problems such as rebooting or freezing (which I don't have)?

Now I don't know whether to replace the mobo or PSU, and don't have extra parts laying around.

 

[RadiclDreamer]

Sounds like bad capacitors to me

If they look anything like this

http://img395.imageshack.us/im...09/kzgexploded1hx9.jpg

Or even bulging at all the mobo is on its way out. You can have it repaired from somewhere like badcaps.net but its usually more cost effective to just replace the board and cpu if you are unable to get the same socket board

http://en.wikipedia.org/wiki/Capacitor_plague

 

[robisbell]

if you have any Capacitors that are bulging, either have the caps replaced or replace the motherboard.