A cold computer crashing

Hi, i am totally stuck and worried about my pc at the moment.
Its a P1900+ athlon, ive had it about 2 years. i have not changed anything with the pc for over 1 and a half years, and the past month i have got a problem thats getting worse.

If the computer has been switched off for an hour or so, when i boot up it gets to the loading screen for windows, and then video card shuts off, fans stop momentarily, you hear the hard drives restart, and the pc sits there with the activity light on the front constantly flashing very very quickly, and the monitor in standby mode. normally i will have to manually reboot.(sometimes it will restart the computer properly itself) this will happen 2, maybe 3 times, and then the pc will load without any problem and run for days fine.

Anyone know the main cause for a cold pc to crash? i was thinking either a hard drive or the power supply is on the way out..?

Scandisk found me no errors.. and today i am going to change the RAM.. any more advice please let me know!

(^^;?(cold PC!)

Powersupply is most suspicious. During fire-up if shortage of power happens, PC is obliged to restart. It's like a used car acts up.

heh yea well im assuming its because of temperature... (low temperature?crazy)
actually now listening i do hear a pretty strange noise coming from a hard drive before it goes to the windows loading screen to crash.. gotta be hard drive or power?
hum, im not using any rediculous cooling system or anything, and i dont live in a cold house either...

thankyou for a reply

If you suspect a the said drive. Just remove this and boot from floppy or other, even knopikkus.

On the other hand strange noise from HDD is also a warning that the HDD is likely to be gone suddenly. Scandisk can find scars on the disk, but no other mechanism perhaps. Try powermax.exe - Advanced test from Maxtor. In any way, you should take back-up while you can.

In addition, there's possibility that the HD's noise is caused by such a instabilty of power.

Sounds like hard drive or power supply, as megumi has said. Either way, backup all your necessary info right away, so you are prepared. I can pretty much guarantee it has nothing to do with the temperature of the computer, cool=good for computers. Do the scandisk with surface scan, and try putting in a new psu if you can.