Cannot start computer

Yesterday, I turned on my computer, and I walked away. When I came back, the computer has turned itself off. (I use this computer everyday, and it works fine). Because it was off, I pressed the power button again to turn my computer on. When I press the power button, the little green light at the front would flash for a second, and the fan would start for a second and turns itself off. When I look inside the computer, I see that there is a tiny yellow light on the motherboard that stays on. From there on, my computer wouldn't turn on no matter what I do.
Any help would be appreciated.
Thank you very much.

 

It's problebly a power suply issue.....

Check you manual for your pc board for that yellow light.....

 

i am sure the yellow light of which he was talking about is the light that tells you the mother board is getting power

 

A long shot but turn the power off at the wall switch for a coupla minutes.

 

It's also possible that something in your system has developed a short, and your power supply is shutting itself down to avoid having the short make it burn out.

Try your power supply in another machine if you can.

 

for testing PSU you connect the green wire and the black wire at 20 or 24 pin of PSU and look at the PSU fan if it work that mean the PSU ......

take all spare parts out computer except mobo and CPU, turn coputer on and listen to beep codes and by that way you can check with the other computer spare parts by putting ram and VGA card in.
How to know about the beep code when computer spare parts get problem, there are some thread in MG that you should know.

 

It may be a valid test, but I can't vouch for the accuracy of A.son's comment. I've no idea of what that connection will do. But don't apply power to a PSU that is not connected to a load. Without a load, the PSU will either shut itself down or fry itself. Either way, you don't get a valid measurement.

How much of a load must be attached? I've no idea. Mobo and CPU may be enough.

 

I know what you meant, some PSU work like your mention, in this case you will put a CD drive in 5-12v PSU plug, it will load when you connect the green and the black pin.

 

This depends on the power supply, a switched mode one will not do anything if you have it layed on the floor with nothing connected to it, it needs the "turn me on" signal from the motherboard ( the power switch to be accurate) to activate it.
Firstly that Amber light means something and should be checked out from the manual before going any further. usually a mobos "ok" light is red and sometimes you get one to tell you which mode your cpu is in or what speed the ram is at (i had 2 in my old mobo one for power and one to say cpu was set above standard multiplier. besides the lamp only means that the 5V stand by voltage is ok. there are many voltages coming out of a psu and one or more of these could be faulty.
To test the system properly you should have your 4 basic components fitted, Mobo, CPU, RAM, Graphics card. Nothing else should be connected at all. This way the mobo POST (power on self test) can test the 3 major components for you and alert you with a specific beep (dependent on modo manufacturer) if there is a problem (of course your going to get "non system disk or disk error" message but ignore that for now. If nothing happens here its one or more of those or the psu. IF the machine starts fine with only those 3 parts attached and you get your "BEEP" then start to suspect cables and PCI cards. Attach one device at a time, start with only your main system hard drive and reboot, still ok? add a cdrom if you have one and follow on in that order, HD, CDROM, FLOPPY (optional), PCI CARDS [1 at a time!] dont worry about windows, it knows your system and will just re apply the drivers as the hardware is reinstalled. if none of this is working (by the sound of it a fuse may have blown in the psu, as a "flash" is a result of the residue power left in the psu's smoothing capacitors acting like a battery for a split second) try a new power supply or check all fuses, even the ones you get inside the psu and check to see the main lead hasnt become loose lol!!.