I installed a new CPU Cooler (OCZ Vendetta) the other day and all was sweet, Then i upgraded the bios on my Gigabyte GA-P35C-DS3R Motherboard, and overclocked my Intel Core2 E6750 to 2.8ghz (from 2.66) and my RAM from 667 to 800mhz.
This was running fine for about a day before my computer began restarting itself for no reason.
The next day it died while i was using it, and reset my CMOS setting, so i figured it could have been the overclock. I turned that back down, and continued on normal.
It was fine for another day, before coming home today, and having my computer on, but no response from monitor. When i turned it off via power switch (button didn't respond) it started to "jump" when i turned it back on. All my fans would spin for a second, and two red LED's started showing on my Radeon HD2900XT.
I wasn't sure where to file this, but I figured here would do.
Could it be my Motherboard, Graphics Card or PSU? I have read some stuff about PSU and angry red lights... but I have an Antec Quatro 850W (which I assumed would be plenty)
Computers continually restart themselves if the components are exceeding the temperature threshold as a precaution.
That new CPU cooler would be a good start to check. Could have come loose or even the thermal grease could have an air pocket between the heatsink and the cpu.
If its not the temperature, its more than likely your RAM. Im assuming the RAM you have is fairly old by now. Running that at a fairly high overclock has probly resulted in your RAM being fried. Take one RAM card out at a time and test the system for faulty cards. This way you can salvage whatever is still working and dump the bad one(s).
if everything is seated correctly and still you just get the fans turning on for a few secs hate to be the bad guy and say it but might be the cpu happened to my gf's computer during an electrical storm it was off but not unplugged. I was working. So could have been voltage irregularities that did something in on your computer.
Gah... Well, i guess that is an option. The ol' 2.66 was a bit long in the teeth.
For a more detailed update, as i just swapped out all my ram...
I turn on the PSU switch.
Press the power button.
Nothing at all happens for 5 seconds
Fans and lights come on for 1 second
Fans and lights turn off.
5 seconds later they come on again. Rinse and repeat.
It seems weird that nothing happens after i hit the button for 5 secs... maybe PSU isn't giving enough power, it "charges up" then uses what it has for a second... thats what it looks like from a total PSU-issue noob's perspective.