Power-on problem - PSU or MOBO failing?

[Morpho]

Hi all.

My PC operates normally for as long as it is on. But if I press standby, which I have used for years on this 2005 machine with no problems, it shuts down instead (NB: BIOS is set to S3). Then when I press the power on button nothing - at all - happens. No light, no noise, zilch. Same happens if I simply shut down the PC rather than use standby. It won't come on again. BUT, and big but, if I leave it for a period of time (I have not established the minimum time as yet), it starts again normally, and runs again for as long as I wish to use it. I left it for an hour earlier today, and it came on and has worked all day. And so I wonder if this is heat related (perhaps something does not cool down as quickly as it should, and so power-on is stopped as a safety device)?

Does anyone have any ideas what might be causing this?

Just for the sake of completeness, in case it is related, I have also recently noticed an "MBR error 2" on startup. I know how to fix that in theory, but I have a MESH PC, and they only supplied a useless recovery disk, not a Win XP install disk, so I can't figure out how to run FIXMBR from the recovery console - as a work around could I use a friends XP disk and "fool" my PC?

Many thanks to anyone who feels they can tackle this problem.

My specs (bought July 2005):

Win XP Pro SP3
AMD Athlon 64 X2 Dual 4400+
ASUS A8N-SLI Deluxe
2Gb RAM
2Tb SATA + 300Gb SATA
Nvidia GeForce 6800GT 256MB
HEC 550TD PTE - 550W PSU

[shaithis]

You should be able to get a DOS bootdisk with FDISK on to perform the MBR fix.

[Morpho]

Thanks Shaithis.

I forgot to mention I am running XP Pro. Can FDISK be run in XP? Also my hard drives are NTFS. Can you please give me a pointer as to where/how to create a bootdisk with FDISK (if that's still relevant)? Otherwise any other ideas as to how to fix MBR error 2 without an original XP installation disk? Thanks!

[shaithis]

Damn.....seems my memory is getting hazy.....XP seems so distant......you do need to get to the recovery console to do it on an NTFS formatted drive in XP or you could pop the drive in another computer to repair it.

I cannot see any reason why you couldn't boot off of any Win XP CD and enter recovery console though.

[Morpho]

Thanks so much Shaithis. I'll try to get a disk from a friend.

Meanwhile, my major concern is still the fact that after shut down I cannot power on again for a minimum of several minutes (last night it did power on when I tried after leaving it for 10 minutes).

Any ideas, or can you please suggest another forum which has a good reputation for solving power issues (or ACPI issues)?

Thank you again.

[shaithis]

The power on/off issue is almost certainly either motherboard or PSU.....I've even had the symptom myself many years ago and if I remember correctly, it was when I had a Hiper PSU!

Can you borrow a PSU from someone to test?

[Morpho]

Many thanks Shaithis. I will see what I can do re the PSU. I'll post back here when I find the answer. Meanwhile the MBR error 2 problem went away after a couple of days. I ran an Acronis True Image backup and I wonder if that overwrote the MBR and so corrected the problem .... Meanwhile the power-on problem remains. I ran driver-agent and it pointed out that I have not updated my Nforce4 Chipset drivers (ever). I am running 2005 drivers! I wonder if there are drivers for the ACPI and whether the fact these are so old might be causing the "standby" to fail and to go straight to shutdown? Can't see how that creates the power on problem however and as you say a faulty PSU or MOBO sounds more likely! Anyway I am going to update the Chipset drivers and see what happens ...

[Morpho]

Hi Shaithis and everyone. I thought you'd like to know what has happened. I now have a working PC - running fine now for 2 days. I tested the PSU and it was indeed the culprit. I have replaced it and the two power problems have resoved themselves - I now enter and wake from standby when requested (it no longer simply shuts down), and I can now power on immediately after shutdown, as should happen. (As mentioned in an earlier post, the MBR error 2 problem resolved itself and may have been software related). I will mention one other thing that happened after installing the new PSU. While investigating the problem I had jiggled and disconnected various motherboard connections in case the problem had been caused by loose connections or perhaps faulty connectors. One of the things that I did was to disconnect my two SATA drives, and try them in the two vacant motherboard SATA sockets. I tried powering on after each reconnection but nothing appeared to happen (no power). However, I suspect that I reversed the configuration of the SATA drives, effectively putting my C drive into second place behind my storage drive during the boot process, and when I pressed the on button the BIOS recorded this change. When I powered on after replacing the PSU, during POST I got a terrifying message that "NTLDR is missing"; basically the operating system boot partition could not be found. There are a number of causes for this message, but the one that rang a bell was that it was looking in the wrong place for the boot partition (i.e. probably on the wrong drive). And so I entered BIOS and sure enough, the boot sequence for the SATA drives was incorrect (they had reversed). After correction the PC booted fine, and has continued to do so. If this is an exceedingly unlikely explanation, then the only other thing I can think of is that when the PSU finally failed, my PC was running an overnight CHKDSK operation, and it blue-screened in the middle of that operation. Possibly that affected the BIOS somehow ...? I hope that this small write-up may help others who inadvertently create the same problem! Thanks for your help Shaithis!