Question My pc doesn't start

MichaelKnight

Distinguished
Nov 15, 2014
88
0
18,540
My pc was rarely shutting down itself, at seemingly random times. Also rarely it was refusing to start, by that I mean it starts but after a few seconds it turns off, when that happened just shutting off the ups(I dont mean psu) and turning it on again was enough to be able to start the pc. But about a week ago it refused to start again, I mean it starts, after a few seconds it shutsdown and no matter what I do(removing and reeattaching the power cords, peripheral cords, connecting the power cord into powerstrip instead of ups... etc) didn't help.

I thought that it looked like a psu or motherboard problem. Some of my pc components are very old and some others are newer though not much new actually. Then I decided to open the pc case, I tried removing some cords like gpu power cords, bluray burner's cords, hdds' cord(both power and sata or ide-ata cords) , graphics card's cords. It continued shutting down after a few seconds.

My doubts started to concentrate on the relatively new(about 4 yers old) psu. I decided to try with my previous psu, it's fan had failed but it was able to run the pc until it overheats so it was enough for my test purposes. I reattached everything to this psu and pushed the power button and the pc started, it didnt shutdown though the monitor was blank.

I was almost sure that the problem was caused by the newer psu but I rechecked the cables and noticed that the cable to powerconnector on the motherboard(4+4pin) which I think used to connect the power to cpu was still connected tı the newer psu, so it was not getting any power. I tried to disconnect the cable but it was stuck and I couldn t remove it, using neither hand nor a pliers. But I was able to remove the top 4pin cable and connected the old psu's cable to the top 4pin connector of motherboard and this time my pc with the old psu attached started, run for a few seconds then shutoff itself.

I tried reattaching the power cables to the newer psu without attaching the 4+4pin motherboard cable (which is used for powering the cpu I think) and it worked too, the pc started and continued running, though no display on the monitor.

So I think there is a problem with the cpu
if I don't connect it pc doesn't shutoff itself. Though I have a doubt that if there may be a problem with the motherboard, especially it's power connector.

Before buying a new old cpu compatible with my pc's motherboard, how I can be sure that it's definitely a cpu problem?
 
Last edited:

MichaelKnight

Distinguished
Nov 15, 2014
88
0
18,540
Thanks for your answer. Keep in mind that the newest part is about 3-4 years old, so it should not be a compatibility problem.

Additional note: One usb port is corrupt, somebody wrongly pushed the pc case and tip of the connected usb cable got broken in it about 2 years ago. That's why my pc was sometimes displaying bluescreen, sometimes it was clearly indicating that it was related to usb port in the bluescreen message.

My system's specs:

2gb ddr2 ram
Gigabyte x38-dq6 motherboard
Intel core2 quad core 2.4ghz
Zotac Nvidia 970gtx graphics card
1tb Hitachi, 500gb hitachi and 2tb Toshiba hdds
Pioneer internal blurayburner, halfworking Samsung internal dvd burner
Coolermaster V760 (or v750) 750 watt psu
Windows 7 32bit
 
Last edited:

punkncat

Champion
Ambassador
The aspect of the telling catching my eye is that it was tripping your UPS.

My first guess would go to the power supply although I would sort of expect it's internal protection to pop if it was overcurrent...if it has any.

That's a pretty old machine, so it might be worthwhile to take a look for bulging caps, burned spots on mobo.
 
  • Like
Reactions: MichaelKnight

MichaelKnight

Distinguished
Nov 15, 2014
88
0
18,540
It turned out, not cpu,not motherboard, not psu but a Ram problem.I think previously I didn't spend enough time on testing ram by detaching them one by one, though actually I had done that somehow I couldn't understand that there was a problem with ram, Yesterday after detaching one of the two ram modules, the pc started.When I re-attached it, pc started for a few seconds then shut off.

I am writing this post using my pc.It has just one 1gb ram module now and it's so slow.So I will buy a new ram module(actually I will buy two 2gb ddr2 ram modules).