Win7 Sp1 has killed two MOBOs - Any Ideas?

With all due respect though this is about the 50th pc ive built

Then you should be aware that you don't even need an operating system for POST to occur, just to be met by an "Operating system not found" message.

Undoubtedly this is hardware related.
You said you replaced the battery and still the same symptoms? That's unfortunate. Make sure to clear CMOS after the battery swap as well.

Since you're stripping the machine down, I'd suggest working with the bare minimum to narrow your seach down of possible causes (1 HD, 1 Vid card, 1 stick of ram). Hopefully at this point you're able to get a system which can POST.

Report back your progress...

as you say you took your psu to maplin to get checked but that still doesn't rule it out as the item at fault, having seen the results of some of these tests first hand i can assure you that it does not mean it will work after a test or that the test was able to find the fault.

the fault may only appear on load over multiple rails where the faulty circuit works on low load but not on high load.

i suggest using a totally different psu to start with and ensure minimum hardware is attached to the motherboard.

OK guys,
the update is as follows.

I removed all 4 ram chips and tried to boot the pc with ONLY the following attached

1 x VGA card
1 x SATA Drive
1 x CPU
1 x RAM @ 1gig

After several hours of non booting/non bios even removing the ram sticks and seating them back 1 by gave the following results.

1 stick - booted
2 sticks - booted
3 sticks - booted
4 sticks - booted

I tried all 4 ram dimms individualy and each time windows booted as if there were no issues. All 4 back in place and system boots now.

Looking at the sitution I can say the following

New MOBO is fine
PSU - Fine - tested in 2 pcs and at local store - given as working fine
New GTX570 - works in alll test machines
Old GTX9800+ - Works in all machines
RAM - Tested as a bunch and solo - All Working
SATA Drives - All work in multiple machines.

I can only therefore assume that GIVEN
The Bios is still working
The MOBO has no underlying issues as is 2 days old
The VGA card/s work fine
The RAM works after unseating and reseating
HDD & OP Drives work in multiiple machines

And the only factor that seems to cause the issue has been SP1 then Im gonna aim my anger at that software. Is it possible that SP1 has sent code to the RAM to tell it to sleep but on reboot there is no Wake call?

Given all the sugggestions and the fact that I have stripped the machine down to the bones and all components are working fine in multiple machines is it fair to say now that there is an issue with SP1 that I may be the 1st to experience?

I have used the windows memory test to verify the ram and I have used in the last month or seo Memtest for the same reason. If the ram comes back after several hours of testing with no faults yet a simple power down causes the system to not boot then there IS an issue with SP1

I thank all of you for your helpful comments and suggestions, if I have come across as short with anyone please forgive me. Headaches from PCs are the last thing I need and spending more cash out on some piece of harware is really not what I need right now.

Thanks again and anny further comments are truly appreciated.

Many thanks
Biz

As a further update and after looking at Mikes link to BIOS codes,

I have an AMI bios. from the first build of this new machoine (Thursday last week) It boots up and gives a single beep during BIOS screen and pre Win7 Loading. This beep according to the link (1 Beep - AMI Bios = DRAM Refresh Failure) All 4 sticks are identical - PC6400 - 800mhz OCZ SLI ram @ 2.1v - If there is an issue with the BIOS refreshing the ram at boot, is it not possible that in hibernation/sleep windows has sent a message to the ram that a bios message will not clear, that is until unseated/voltagae completely gone and reseated?

Hi there
Sometimes if the Power LED is not connected correctly or poorly connected --loose connection etc then you MOBO won't even power on at all.

You also need to ensure that all fans have been wired in correctly and are working as soon as the mobo is powered on. If these aren't working properly the CPU will stop -- to prevent overheating.

Ensure the heatsink is properly and tightly attached to the processor and of course the processor has been fixed to the mobo without any pins being damaged -- these days this should not occur as the processors are normally "ZIF" type or "Zero Insertion Force.

Finally ensure that no metal components are shorting such as screws attaching the mobo to the case.

It probably is IMPOSSIBLE for a normal Commercial OS such as Wiindows to damage hardware on simple boot.

(Of course you can run "destructive" tests under software control say on Hard disks but these are specialized tests -- a normal OS won't do this).

Cheers

jimbo

I removed all 4 ram chips and tried to boot the pc with ONLY the following attached

1 x VGA card
1 x SATA Drive
1 x CPU
1 x RAM @ 1gig

After several hours of non booting/non bios

Is that using the HDD, of which, you're holding SP1 responsible?
What exactly did you do that after several hours of non booting, it started to boot?

Given all the sugggestions and the fact that I have stripped the machine down to the bones and all components are working fine in multiple machines is it fair to say now that there is an issue with SP1 that I may be the 1st to experience?

Unfortunately no. Here's why: POST doesn't require a HDD (i'm fairly sure) or at the very least, if DEFINITELY doesn't require an OS. As the last step during POST you'd be met with "Operating system not found". Until that point, anything on the HDD is null and void, even if it's corrupt, since it's not being read.

Until we know more of how you got the system to start booting, further suggestions will be limited.

It boots up and gives a single beep during BIOS

A successful boot will also have 1 short beep. Make sure to not get that confused?