Laptop Shutting down after 10min in a game after windows updates

i have an Acer Aspire 8930 laptop,
it has been running smoothly since december 08, however a week ago some new windows updates came out and i installed them, i play wow online and have been since i got laptop and have never had a prob playing it, i play for something like 7 hours a day, yes excessive but its addictive, and i always play in windowed mode with my desktop in 1680x945 with wow running in 1365xetc, and playing for 7 hours straight so i know its not an overheating problem before i get that answer off anyone,
back to the problem, after updates my laptop shuts down without warning after about 10mins in game, after 3 days of this i got angry and called acer support who were great and explained everything i could do before i had to send it back, so after a few minor changes nothing changed it still did it, so i did an acer boot recovery, which formats my hdd and reinstalls windows and everything back to factory defaults, hey presto my laptop was working again and i could finally hit another lvl in wow(i know im sad), so for 2 days i was back to normal doing everything i used to, then this morning windows told me it had 3 inportant updates to do,
so i let it do the updates, restarted and then started playing wow......you guessed it 10mins and my laptop shut down, the updates it did this morning were....

* Update for windows vista (KB940510)
*Microsoft .NET Framework 3.5 Service Pack 1 and .NET Framework family Update (KB951847) x86
*Windows Malicious Software Removal Tool - Febuary 2009 (KB890830)

Specs for laptop are...

Intel core 2 duo P7350
Nvidia geforce 9600M GT 512mb
4gb DDR3
320gb hdd
blu-ray disc
fingerprint reader

Any decent ideas are welcome, im at the end of my tether

thanks

Digi

PS plz dont say anything about overheating that is not a prob for me thanks

did a system restore seems to have worked, also turned off windows update so it doesnt arise again

I always have my settings at 'check for updates but let me decide whether to download and install them'....