Computer Keeps Powering Off, Unstable, Intermittent?

Infopackets Reader 'rbruner' writes:

" Dear Dennis,

I have an older, but still viable Systemax XP computer that was upgraded to Windows 7. The problem is that the unit powers down within a few minutes of powering on. I have already replaced the motherboard and power supply, kept the CPU (an AMD 4400+, circa Q4 2008). When I boot into safe mode, the unit is operational, but but if I boot up Windows 7 normally or insert a Ubuntu Linux Live CD, my PC will crash. Should I try another CPU? "

My response:

Based on what you're telling me, the issue might be hardware-related, but I find it conflicting that you say the PC is stable in Windows Safe Mode, but not otherwise. It could be that your PC is overheating, or possibly bad or unseated RAM (Random Access Memory); or possibly, the problem lies with Windows itself. At this point, there are too many variables to give a decisive answer.

To further test the stability of your system and to help rule out that there is a hardware problem, I think you should download and boot from another Linux Live CD distribution to see what happens. Examples of such distributions include Damn Small Linux, Puppy Linux, and Slax; these particular Linux distributions are very small and will easily fit on a CD or USB thumb drive.

Lastly, when you say that your PC crashes: are you receiving a Blue Screen of Death (BSOD), or does it power off completely without a blue screen? If you get a blue screen, what is the error message?

Infopackets Reader 'rbruner' wrote in again:

" Dear Dennis,

When the PC shuts off, it happens instantaneously - clunk! It simply powers off, with no Blue Screen of Death. I can unplug the PC for about a minute - so that the power supply 'resets itself', otherwise, it won't turn back on. After that, I can usually power it back on. Note that I have run 'memtest' without any problems. On the Ubuntu Linux live CD, it would almost finish booting, and then pow - it shuts off. The problem seems to have worsened over time, with the power being stable for at least 1.5 hours or so. But now it's happening more often, and sooner as time goes on. I do not believe this is a heat related issue; I used temperature monitoring software to view heat levels inside my computer, and none of the parameters went above 50 Celsius; it generally remains in the 40s. "

My response:

If the PC is powering off instantly and without an error message, it's definitely a hardware problem. This is assuming of course that you have no issues with the electricity in your home and it remains stable and consistent. That said, I fully believe and HIGHLY recommend using an Uninterrupted Power Supply, or UPS, with proper voltage regulation and battery backup (most do). These are worth their weight in gold as far as I am concerned, and I have them attached to every PC in my home.

The temperature monitoring program you mentioned is only good for monitoring any hardware that has a temperature gauge associated with it. Such gauges are not present in power supplies (that I am aware of). Nonetheless, the power supply could be overheating, or faulty for that matter, resulting in interrupted power and subsequently an instant power off. In that case, a simple fix would be to change the power supply and then test the stability of the system again.

That said, I am more inclined to think that the problem you're experiencing is a result of faulty capacitors on your motherboard. I say this because of two reasons: first, the problem has worsened over a period of time. Secondly, my wife's PC acted exactly like this a few years ago. I inspected her motherboard and found that 2 capacitors were starting to leak and others had a slight bulge to them. I knew it was only a matter of time before the problem would get worse and require intervention.

Initially, she had problems powering on the unit; it would simply display a black screen without any other activity. She would then cycle the power a few times, and finally it would boot. Once the unit was powered on, it was good to go - stability was never an issue. That temporary 'fix' lasted for about a year, as her PC was always on and running 24/7 a day with a battery backup UPS. About 3 months ago, her computer crashed in the middle of using it (much like you describe), and was then unable to turn back on. At this point, I inspected the capacitors again. I found that many more were bulging, and some had even leaked all the way onto the main board.

The Great Capacitor Plague of 2000s

You mentioned in a previous message that you have already replaced your main board. If the replacement was not a new motherboard from recent years, there's a very good chance you also have bad capacitors. Some time in the early 2000's, there was a Taiwanese manufacturing firm that produced bad capacitors.

These capacitors were used by big-name PC manufacturing firms such as Dell, HP, and many others. Word got out from users on Internet forums that a wide range of PCs were suffering from similar problems, and the symptoms were later dubbed the 'capacitor plague'. If you open up your PC, you can easily visually inspect the motherboard to find any bulging or leaking capacitors. Examples of a bulging capacitor are here; note that they can leak from the top or bottom.

How to Replace a Motherboard Capacitor

If the capacitors leaked onto the main board, you can use a cotton swab and rubbing alcohol to clean it off (while the unit is power off and unplugged, of course). But that alone won't fix the problem; you will need to replace the capacitors with (preferably) new units, or perhaps from a donor motherboard that is no longer in service.

This will require de-soldering the old one and soldering the new ones; Youtube has an excellent video on de-soldering, demonstrating techniques using a solder sucker, soldering braid, and solder. It's not an easy job if you don't have much experience with a soldering iron. Don't forget to clean any soldering residue after the job is finished (again, using a cotton swab and rubbing alcohol).

The other option is to buy a replacement motherboard off ebay - but be sure to review the integrity of the board before you purchase! I don't think they sell new motherboards for that particular processor any longer.

I hope that helps.

About the author: Dennis Faas is the owner and operator of Infopackets.com. With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.