Help! My PC randomly shuts down and rarely powers back up.

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Here's the deal:

I've had this computer for about 5 years, and never had a problem like this before. (As a side note, I replaced the CRT monitor that came with the PC with a new LCD one on January 2nd.) On February 3rd, my PC just shuts down out of the blue. Not thinking of this as a big deal, I tried turning it back on. No matter how many times I turned off the power supply, and pressed the power on button on my PC, it wouldn't run like it usually does.

The following are the different ways this faulty computer reacts to me trying to turn it on:

1) The fans run, and everything seems to power up fine for about 4 to 5 seconds... then it randomly shuts down. I don't even hear the first beep.

2) It turns onto the BIOS screen
a) After exiting BIOS, my computer turns on and everything runs like it should.
b) Before even getting a chance to exit BIOS, the PC shuts down... again.

3) Everything runs smoothly like it did before, and my PC only shuts down when I want it to - no problems.

4) Everything runs smoothly for 5 - 10 minutes. Random shut down once again.

5) When I turn on my power supply, my PC sometimes turns on by itself. How odd.

6) Nothing runs. No fans, no nothing.

Is my motherboard fried? Is my LCD screen using too much power? Is it just time to get a new computer? I need help! I think I'm going to go mad with rage.


Posts: 436   +0
Hi and welcome to Techspot. This sounds like it might be a faulty power supply. Do you have another one you could try in your case?
power sags or surges

This could also be a case of faulty wiring in your residence. From the description you gave you might also want to check the wall outlet with a multimeter. This device will give you a power reading from the wall outlet. It should read around 110v to 120v at 60Hz (it won't be exact) This could also be a faulty psu. Try and find a psu that you know is working properly and install it to see if the same problems occur, preferably a 400w or better.


Posts: 6,908   +10
You likely have troubles in the video graphics, brought on by the demands or changes of the LCD output... Just creating change on an older machine will introduce problems... hard to pinpoint when the LCD was installed a month earlier...
The power supply will take care of most of the problems of a wall connection, so doubt that is it... as it is reducing output.
I would suspect standard things on a machine that old... and suspect that the LCD is not related. Most common: memory module failure, CPU Fan, video graphics failure unless integrated onto the motherboard, hard drive that may be dying, or irritating failures with such things as a sound card or modem can all cause the problems you describe.
Also, consider dust and hair in the power supply, or dust and hair in the CPU fan... use a can of Dust Off or other difluoroethane gas... do not vacuum it.

as stated above it is possibly a power supply issue. I would strongly suggest that it may be a failed CPU fan. The symptoms you describe seem to point that direction.

Check to see that all the case fans(including power supply) and the CPU fans are running. check for dust clogging the cpu heatsink.
Seeing as how you had the lcd for about a month before the pc problems occured it probably isn't the lcd. If your ram was going bad you wouldn't even go into post without hearing some sort of beep error codes on start up. Your hard drive could also be corrupt so run chkdsk or some other tool to check the integrity of the HDD.
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Thank you all for your replies! I will try all of this out and get back to you guys. It's probably time for a video card upgrade, anyway.


Posts: 6,908   +10
Don't spend the money on something you may not need. There is no indication that an "aged" power supply is any different. Figger it out first.


Posts: 17,233   +234
5 years is a good run for any system. It is also enough time for any component(s) to fail... I really don't think the LCD display is the cause. I would try power supply first


Posts: 782   +3
My first instinct is the power supply. 5 years is pretty good for a PC. Of course then again most of my PCs die within 6 months due to the low cost and low quality parts i used to use. This PC I have is doing great because of the good parts.

Anyway check the PSU.
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