Computer shuts down by itself

[dr DonG]

My computer keeps shutting down by itself at the most randomest of times. Now i can't turn it on. All my computer does is flicker its lights on the case, and the keyboard status lights. It was running very stable for the past 2 and a half years. I suspect its the power supply is the cause. Thanks in advance.

I built my computer
it is enclosed in an antec slk3600 case and an antec 300 watt power supply.
im running a pentium4 2.4ghz
i have a ati radeon 9500
a sound card
a modem card
tv tunner card
80gb wd hd
cdrw drvie
dvd rom drive
floppy drive
win xp home
and 2 extra 80mm case fans

 

[Buxton]

Start trying to switch stuff out, power supply first if you think its the culprit. Also check for the beep or light patterns. You should be able to find out what they mean on the manufacture's website.

 

[dr DonG]

The thing is i don't have a power supply to switch out to see if its the culprit. the lights just flicker and the power suppy fan starts to rotate stops starts to rotate again stops etc.
When i push and hold down the power button it powers up but the bios does not load or anything, then when i let go of the power button it goes into the flickering state. again, i think its the power supply, i disconnected a fan last week when the problem started, and it worked fine for a few days, but now i don't think disconnecting components i don't use will help anymore.

 

[stevty2889]

Does sound like the power supply could be going. Have you made any changes to the system recently? It's also possible something is wrong with the power or reset switch. I would try disconnection those from the motherboard, and then short the 2 power switch pins on the motherbaord with a screwdriver to turn it on, that will eliminate the switch as the cause, but it's more likely the PSU since you where having random shutdowns. It could also be heat related. Check to see if your CPU heatsink is full of dust. Might not hurt to remove it, clean off the old thermal grease, apply some new thermal grease, and put the heatsink back on.