What is wrong with my PC? Mobo perhaps?

[Normalcey]

This is the closest thread I could find to my problem... but yeah.

My PC is acting strange. It is fine once I get it going it seems, but shuts off at night time. Which I am sure is the same problem as this :

When I DO shut it off I have to turn it on about ten times before I can get into safe mode, and reset my computer and get in normally.

The first few power ons it shuts of about 3 seconds into it without and screen display, other times its while windows is loading with those bars on the screen (XP)

My theory is its cold? I have a desk fan pointed into the Case for when it gets hot... Is this damaging? Could it cause it to not boot up if its cold?

 

[rolli59]

Cold should not affect it. Go through this guide and see if you can narrow down the problem http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems
Remember to check all connections.

 

[moody89]

The colder the better (within reason!) for a computer system. Memory or PSU are prime suspects at this point. If you could post a list of your full system specs, this would help. In the meantime:

This is a good guide on boot issues. Check everything on this list one at a time and double-check everything is connected correctly. Post back here when you're done and we'll go from there.

http://www.tomshardware.co.uk/forum/261145-13-read-posting-boot-video-problems

To test faulty RAM try using only one stick at a time and try each stick in each and every slot on the motherboard. This will rule out either bad memory or a faulty motherboard. Failing that, try removing all non-essential components and replacing each one by one to locate the faulty component. This includes everything except your motherboard, CPU and RAM.

The guide is the same one rolli59 posted so nothing new there, just a few more things to try as well. Also, can see you see any error messages in the event log when these shut-downs occur?

Post back and we'll go from there.

 

[jsc]

When I DO shut it off I have to turn it on about ten times before I can get into safe mode, and reset my computer and get in normally.

The first few power ons it shuts of about 3 seconds into it without and screen display, other times its while windows is loading with those bars on the screen (XP)

Sounds like PSU.

System specs?

Work through our standard checklist and troubleshooting thread (rhe one that everyone links to):
http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.

I have tested the following beep patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboarding

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU.

Make sure you plug the CPU power cable in. The system will not boot without it.

I always breadboard a new build. It takes only a few minutes, and you know you are putting good parts in the case.

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU. Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
Running fans and drives and motherboard LED's do not necessarily indicate a good PSU. In the absence of a single short beep, they also do not indicate that the system is booting.

At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=youtube_gdata

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card.

Silence or long single beeps indicate a problem with the memory.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.