Computer boots up, then shuts down

[largo249]

Sometimes when I turn on my computer, it will boot up to the desktop and then shutdown. Most times however, it never makes it that far. I've replaced the power supply, reseated memory and changed outlets as well as battery backup plugin locations. Any ideas on what it could be? I'm thinking motherboard..........

[drmsucks]

Any error messages?

Please read this: http://www.computerhope.com/forum/index.php/topic,33328.0.html

[largo249]

I built this system about a year ago and have not had any problems till now. I do receive the single beep when booting and there are no error messages; it just simply shuts down. I removed the side cover and all fans are running when the power is turned on.

[drmsucks]

I built this system about a year ago and have not had any problems till now.

Anything changed before the problem - hardware, downloads, security programs settings, new programs, driver updates, etc?

Can you start in Safe Mode?

[largo249]

No changes or additions of any kind; was able to start in safe mode ok. Could it be the MBR?

[largo249]

Nope, it shut down again while in safe mode.........

[drmsucks]

Can you access BIOS? See if you have a 'Hardware Monitor' section or similar. Wait at that BIOS screen, monitor temps and fans and see if the system shuts down. If so. what was last temp? Are all fans shown running?

[largo249]

CPU fan 1622 rpm
System fan 0 rpm
cpu temp 109 degrees
system temp 107

Letting it run to see if it shuts down; will recheck connections for system fan....

[Carbon Dudeoxide]

cpu temp 109 degrees
system temp 107

Celsius or Fahrenheit?

[largo249]

Fahrenheit

[Carbon Dudeoxide]

Hmmmm....43*C isn't that hot but we can't discount any possibilities.

If you have an external fan, have it blow at the computer and see what happens.

[largo249]

So far, it hasn't shut down while in the BIOS. It's been almost ten minutes now. I also reloaded the default settings. Forgot to mention that when I replaced the power supply, I also cleaned the heat sink and processor and put on new thermal compound. I used Artic Silver 3 since I have a dual processor. Will keep you posted....

[drmsucks]

109 & 107 sure shouldn't be a problem.

Why don't you see if it shuts down without the external fan first.

If it does, turn on the fan as @carbon suggests and see if that helps..

Is the "system fan" a case fan? Did you find out what the issue is? If it's powered from the psu and not the motherboard, there will be no monitoring, i.e., speed = 0.

[drmsucks]

Forgot to mention that when I replaced the power supply, I also cleaned the heat sink and processor and put on new thermal compound. I used Artic Silver 3 since I have a dual processor. Will keep you posted....

This was after the problem, right?

I also reloaded the default settings.

Are you overclocking at all? What settings do you normally run different from default?

[largo249]

Yes to "this was after the problem" and I don't have my system setup for overclocking.

Everything is pretty much the default settings. It was in BIOS for twenty  minutes and did not shut down. I've exited out and back into Windows.

I did turn a fan on, but it's not any hotter today than any other day. I'll keep it the system on and see what happens.

Will keep you posted............