XP and Win7 both shutdown without warning during boot. Safe mode fine.

I've had a weird issue suddenly crop up with my dual boot laptop.

Specs:
Acer Aspire 5051 AWXMI
AMD Turion 64 TL-60 Mobile CPU (upgraded from AMD Turion 64 Mobile MK36)
Dual boot with XP and Win7 RC1. Up to date with all patches from MS.
120gb Hard Drive
1024 mb Ram (2x512) share onboard video
Rest of laptop is a standard from the Factory.
2 years old. Brought brand new.


I have had no problems with it at all recently. It has been running very sweetly since I upgraded the CPU, which was a good 6 months ago.

2 nights ago, I attempted to boot into XP as I normally do.
It got to the Windows Logo, and then shut down.
I tried again. same thing. Windows logo- shutdown.

I then attempted to boot into Win7. Gets to the desktop, just before loading icons. I can even see my background image. Shutdown.
Exactly the same place each time.

I then tried Safe Mode for both Win versions. No problems at all. Boots right up, able to run the limited programs. shut down. restart again in safe mode. All is good.

Try to boot into standard. No dice. Both XP and WIN7 shut down at the same points as previous attempts.

I had a similar issue (XP only), when I first upgraded the CPU. Back then, I just needed to upgrade the Drivers to accept the dual core. It was working fine. I attempted to upgrade to the latest AMD cpu drivers for the Turion. But this hasn't helped

So i figured, if it's a driver issue, a fresh install should solve it. It has been a long time since the last fresh install anyway. It's windows! A year without a fresh install is a pretty good year! time for some housekeeping.
I backed up all my data and reformatted the partition.

The XP installation freaks out at the 34 minute mark. No freeze, just a complete shutdown.
I have tried two XP discs, both of which have been looked after with no scratches and have had successful installs previously, so i can't blame the cd (Corp Edn with volume licence key).

I have checked the ram. It works fine. Run through tests with Hiren's Boot CD

I was able to finish the install using debug mode. I can now boot into safemode, but cannot go into standard.
I have not tried a fresh Win7 install.

Zenwalk Live Linux CD works perfectly fine. Will attempt a full install of a linux distro tonight, just to make sure.

Summary:-
1. Win 7 shutsdown just after desktop loads
2. XP shutsdown just after Windows logo
3. Safe mode works fine for both versions.
4. Fresh XP install works fine using debug mode, but shutsdown on standard after windows logo.
5. Fresh XP install shutsdown at 34 minute mark (installing devices).
- Have tried to view install boot log, but nothing seems to jump out as out of place.
6. Zenwalk Live CD runs without any problems
7. Full install of Linux distro still to be tested.

Things to try when I get home:-
1. remove battery (could be a dead battery issue) and run direct from mains.
2. I have bought some thermal paste. Apply to CPU to prevent overheating
3. Adjust the BIOS settings to limited hardware
4. Attempt Win7 RC1 install again. see if it craps out the same way.
5. Download the Ultimate Boot CD and run some burn in / benchmark styles tests against all the hardware.

Can anyone else think of any thing I can do before forking out clams on a new laptop?
I get the feeling it is either the CPU or video card failing... but that doesn't really explain why I can load Zenwalk or both windows versions in Safe Mode...

Any help will be much appreciated.

cheers

sidz