[Stinky Britches]

Hi all. Long time lurker, first time poster. Desktop PC: 3 year old HP Pavilion a400n. OS: Win XP Home w SP2. It's a inexpensive Intel Celeron 2.7 GHz processor for personal use: email, eBay, surfing. I'm not a gamer. I use Trend Micro Internet Anti-Virus and freebie version of Ad-Aware to keep it clean. Problem: Many weeks ago the PC began turning itself off and on. Very strange. But it cannot stay on. When I want it on it kicks off after just seconds or minutes. I did research on the GTG Forums and deducted I needed a new PSU. Bought an El Cheapo no-name from a reliable online PC site. This PSU is 450W Max. I'm limited in choices because my Mobo demands I use a 20 Pin Plug. Cleaned out the (average) dust from case like I do 2-3 times a year and installed new PSU. Oh no! Same problem still exists! Tried the new Power Cord. No help there. Plugged Power Cord into a Power Strip instead of my Back-up Delay Power (sorry I forget the tech name). Still no good.

Now I wonder: Should I purchase a better, beefier Power Supply? Perhaps the PSU I installed was defective new or is just poor quality? I also wonder if it is possible that my Mobo Battery might be shot - but typically those Power Cells are rated for a 7 year life.

I have carefully checked the cables one at a time to make certain they are as they should be. I also spent more time cleaning the unit, getting really picky. But my original problem still exists.

I have the same huge Trinitron (?) CRT that I've used for years. I have a HP All-in-One but presently that is not even hooked up to PC by it's USB. In the past I've used this HP gadget I have along with a VHS deck to put my old tapes to DVD, thousands of them - but I have not done any of that in over a year, and that HP gadget is not hooked up to my PC for quite some time. I use the original Keyboard with a Wireless Mouse. Mouse has been used for some 2 years. I have not added any new software in quite some time, and I do Preventive Maintenance regularly to keep my PC running efficiently.

Sorry for being so chatty but I figure being throrough is better than being glib. I thank you all for your time and consideration and look forward to reading any recommendations you can afford me.

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Any decent PSU will let you slide off the 4 extra pins for use on a 20 pin motherboard.
If you think the new unit is defective, send it back.
If the MB battery was shot, it doesn't affect the operability of the computer - it'd just complain every time you fired it up.

[Neil Jones]

Any decent PSU will let you slide off the 4 extra pins for use on a 20 pin motherboard.
If you think the new unit is defective, send it back.
If the MB battery was shot, it doesn't affect the operability of the computer - it'd just complain every time you fired it up.

[skie_m]

I would suggest also adding in Spybot: Search & Destroy (they provide a free download) ... this takes care of some additional backdoor programs that might cause problems on you.

It may be possible that your UPS (uninteruptable power supply .. that thing you didnt know the tech term for) has drivers for controlling it that are corrupted ... possibly a re-installation of your UPS control program and drivers may solve the problem, but you say that even while running without the UPS connection you have this same issue ... it still may be worth it to you to check it over.

I would also run a check on your Windows Registry, and also check your computer's power management options to make certain that changes weren't made that you are not aware of.

If you have a LAN setup or are using an ethernet card for your internet access, be advised that computer power-on can be controlled through a special LAN bios chip upgrade and you may have someone just messing with you through that connection.

Last, but not least ... it could be an intermittent short in any one of many peripheral or internal components. As your last resort, simply because it's so time-consuming ... strip your computer down to it's bare essentials. CPU + motherboard + ram + floppy drive + video card + monitor .... boot it up and see if it has power problems (using the floppy drive). If it seems ok, begin adding your main components ONE at a time until the problem rears it's ugly head. Quite obviously, it will be one of the last components you re-installed. Additional tinkering at that point can pinpoint the exact component that is causing the issue, which will need to be replaced, of course. If you don't have a floppy drive, don't panic .. just use your hard drive.

If you have problems powering up immediately, then you know it's one of your bare minimum components ... use another known working system to test the components (in this case, test the RAM, video card, and the boot disk -- you'll probably have to replace the MB and CPU as a set). Intermittent problems are the worst possible problem to troubleshoot, simply because they come and go ... typically without any warning. One day it works, another it doesn't, and you changed nothing in between, and then a few days later it's fine again for a week ... it's enough to drive anybody crazy.

[Stinky Britches]

Hi Neil Jones. Thank you for your reply. Online at PC parts sellers I've seen many PSU's that have the 20&4 pin array. I was not aware that I could slide off the 4 extra pins. Thanks for your advice on PSU's; I am going to follow up on this. Thanks too for the tip regarding the Mobo Batt. Happy New year!

Hello Skie m and thank you too for your reply. I would like to follow through on your idea of adding Spybot: Search & Destroy; reloading my UPS control program and drivers, and running a check on my Windows Registry...but I'm sad to say that is not possible at this time. The PC will not stay on. It on comes up for a few seconds beore turing off. If I keep at it long enough I can get my CRT screen to show my usual start field and icons, but the PC will shut down before I can get very far in opening any programs, etcetera.

I do not have a LAN setup and at this time I'm not even connected to the internet. My wife recently set up a home office with high speed DSL (which I am not connected to at all) so when my 56K Dial-up economy service contract ran out I did not re-up. In the future when my PC is behaving properly I will hook up to my wife's PC's DSL.

As for this being an intermittent problem...it is not going away and coming back. The problem started weeks ago and my PC has been in a state of unuseable ever since. I agree, intermittent problems are indeed a major headache for any repair person - they are simply the worst.

I think I am going to follow Neil Jones advice and see if the replacement Power Supply might be defective from the box. If this does not work I will proceed with your advice, Skie m, to strip my PC to its bare essentials in an attempt to define which component has gone defective. Thanks very much, Skie m, and a Happy New Year to you.

If any other GTG Forum Members have an idea regarding my dilemna that has not been covered here I would appreciate your input. Thank you all!