PC powers off on reboot

GeForce6100sm-m V:1.0 M/B
2Gb RAM (2 x 1Gb sticks)
320GB SATA HD
450w PSU
AMD Athlon 64X2 Dual 6000+
XP Home Edition Version 2002 Sp2
NIS 2007 (currently uninstalled)

Bought new in August 2007, running quite happily with no problems whatsoever until just before Xmas, as best as I can remember I was downloading an updated Nokia Suite and hadn't taken much notice but Windows Update was also downloading whichever piece of paper Microsoft had decided to cover the latest crack with.

The MS update installed and I got the reboot to install pop-up, as the Nokia software was still downloading I hit the "x" to close the pop-up rather than the "ok" to do it then, it rebooted anyway, or at least tried to.

I can't say for sure just where in the boot up sequence it got to when it just powered off. It wouldn't boot afterwards either, just giving corrupt/missing system file messages when trying to load XP (always getting through POST, sometimes reaching the XP splash screen, sometimes not)

I then had to leave it for a couple of days and was able to boot from the XP CD, I didn't have time to attempt any repairs then but at least I knew (or thought I knew?) that the problem would be fairly easily fixed.

On the next try it wouldn't boot from CD (can't remember the error messages or whether it was just powering off) fiddled around in the BIOS and managed to get to the repair console, it asked for the admin password - I'd never set one, so that was the end of that.

Called a mate that said it sounded like a HD problem so I bought a new HD, installed XP, fine for a little while then the same problem appeared, corrupt/ missing files and power off on reboot somewhere on the splash screen.

Back to trying the original HD. I found that unplugging the power lead and leaving it for a short period enabled me to get to a point where I could restore/ repair XP from the CD. It instantly powered off once when I tried to open NIS intending to run a scan, hence the uninstall.

Subsequently I've found that rather than reboot if I select shut down, leave it for a minute then press the power button it boots up without any problems at all. Leave it on stand by over night rather than powering off also means it just starts in the morning.

This has been my first chance to spend any real time trying to solve the problem. The PC ran fine all day yesterday and woke up without any problem today. There are software (registry?) issues with some of the applications that aren't be solved by uninstalling, shut down, make a coffee, boot up and reinstalling. Of the ones I've tried Norton Systemworks and Sonicstage are the two I'd most like to get running right now.

A bit long winded, my apologies and also I'm clearly not 100% sure whether this is a hardware, software or malware problem. Spybot & Ad-Aware SE found nothing major, I installed Norton 2008, ran a full scan that found nothing before uninstalling again (Norton just loves to reboot the PC when it updates, not very handy at present).

I've scanned quite a few threads here, checked connections, pulled one memory stick and then the other and just don't know where to look now.

Bottom line seems to be that the file problems were caused by the PC powering off at inopportune moments during boot up, the hardware is working without problems when allowed to start by the OS, there doesn't "appear" to be any malware in the system, so there's something in there somewhere that happens during reboot but not boot causing the power to shut down? And if it powers off during reboot the leads have to be physically removed.

Any ideas anyone? (I've tried to remember as much of what has and hasn't happen over the last 3-4 weeks)

 

I've only just reinstalled NIS 2008 on the PC, left it doing something (not quite sure what - possibly full scan, may have been update) wasn't paying any attention as I'm on a 2nd PC when it just powered off, booted on 3rd attempt.

 

Can you do a "System Restore" to a date prior to that MS download? If so, the first thing to do is to disable MS automatic D/L. They are a PINTA when you are trying to do something else.

 

Thanks for the reply.

I did try system restore and got absolutely nowhere at the time. Now XP is (seemingly) okay having reinstalled, other than a few apps that won't run or reinstall and run (some old files somewhere causing problems?) the only real issue is that any reboot attempt results in the PC powering off at the splash screen, potentially taking out system files yet again.

 

Last shot at this, a few more problems turning up when trying to run/install/ uninstall apps.

I'm assuming that the powering off at reboot has taken out/ corrupted a lot of files, some apps that I've thought that I've uninstalled have left a mass of folders and files that the uninstall should have wiped. Some apps don't appear in add/ remove so I can't uninstall them (or reinstall - kernal 386 something or other fault).

I'll rescue as many wanted files as I can then I'll pull the HD out and try rebuilding from a clean HD but is there any point until I've found out just what is causing the power off on reboot?

A final plea - does anyone have any idea at all just what is causing this?

Is there anywhere that I could be pointed at to read up on what happens within the PC on boot up (hardware and software) and what differences there are when it's a reboot? This isn't an intermittent problem, it happens every time a reboot is attempted and it never powers down if the PC is switched off, left a few seconds then booted.

Is it worth upgrading the BIOS? There is a newer version available but is it even remotely possible that it will be a fix or could it just cause new problems?

Any suggestions would be welcome even if it's just to eliminate possible causes.

 

I've deleted a load of files that should have been removed on uninstalls along with a couple of apps that won't run, then run a registry repair app and defraged the registry and to my surprise/ shock/ joy the PC now reboots without any problems at all!

I'd still like to know just what caused the original problem just in case it returns at a later date and of course it would be handy for anyone else that suffers a similar problem in the future.

Thanks to all that have read this and possibly tried a bit of research on my behalf.