• Video Card : Nvida GE Force 210 (Dual Head) with 2gb ram

Could be the culprit, make sure you have the latest NVidia drivers, I had issues with Win7 and Nvidia.

Overheating could also occur due to a build up of dust & other crap inside your pc case, meaning your fans aren't doing their job properly.
 
If you intend to re-seat your cpu with a new layer of thermal paste, this might be a good time to thoroughly clean the insides of your machine and make sure all your peripherals are also seated properly - RAM sticks, GFX card etc.
Also check your PSU for dust buildup

How could overheating be software dependant? Overheats running X3 but not when running 8.5?

Love it...
Steve merely suggested it could be overheating #6. That doesn't make it a fact (or a non fact).
I'm not taking that approach as the timing seems a little odd, same time as a software upgrade (although who knows it could be overheating for all I know)....
 
BTW it's a misconception that because a driver works for app X it will work for app Y, or even a revision of the same app. And drivers can run hardware to be hot (not saying that's going on either).
 
So everything has dependencies and no you can't really jump to any conclusions. The best guess so far IMHO has been ndivia drivers and the driver  update util I have suggested should sort this (amongst updating other drivers that could be a problem). It could even be firmware.
 
But as no info has been supplied really (see Bob's post) we are all guessing.

I don't know why it would be doing it on one version and not another, but the only time my computer has ever just shut down like that it was due to overheating.  It wouldn't do it on just any project, but if I loaded up something that was using a lot of CPU it would just shut down on me.  It could be that the newer version is using just enough CPU more that it pushes it into that territory and goes from very hot, but still working to so hot I'm gonna shut down on you.

Yup that's one scenario agreed, but I've seen NVidia drivers do exactly the same thing as has markyzno evidently.
And any device driver or dodgy firmware can do that, and generally when that goes wrong is when software is being updated (smoking gun).
Anyway without feedback from the op who knows, it could be overheating. it could be electricity bills or the next door neighbours cat...

All my graphics card woes stopped when I moved to Win 8.
 
NVidia drivers were randomly rebooting my system as the OP describes plus I was getting the hideous black screens of death.

well, early during the x1 cycle there was some change (to do with roland interfaces iirc) introduced that caused Lynx cards to fail, that was followed by the first hotfix patch... could be something similar, would explain why x1 works but not x3, not necessarily the driver but how the app accesses/uses the driver http://www.cakewalk.com/Support/kb/reader.aspx/2007013217

Well, since a cow burned down the entire city of Chicago in 1871, it well COULD be the next door neighbor's cat.
 
I believe though that I will wait to see if the original poster chooses to supply the information I requested, just in case the neighbor's cat has a good alibi....
 
Bob Bone
 

never let a cow get matches
 
eta: "In 1893, Michael Ahern, the Chicago Republican reporter who wrote the O'Leary account, admitted he had made it up as colorful copy.[3] The barn was the first building to be consumed by the fire, but the official report could not determine the exact cause"
 
;-)