I have a Gateway NV7915u laptop. The computer experiences an instant fail or instant power off at various times through booting. Occassionaly I can get the computer to boot and retrieve a few files off of it. But I think ten minutes is the max. More often than not it shuts off during boot or moments after logging in.
I've removed the battery and ran it off of the power cord. Still experienced the same problem.
1.) Blow out all vents. Didn't seem to make a difference.
2.) Removed Battery and ran PC off AC power. Seemed to help it stay running longer (hrs instead of seconds) but did not solve any problems.
3.) After step 2 I tried to restore the computer. The restore and install process was 50% complete and the instant fail happened again.
4.) Tried to reboot off of CD and start install over and PC continues to experience Instant Fail.
One thing I've noticed is that it appears to fail when a new process begins. Almost like it's a motherboard or hard drive issue and not a over heating issue. I suspect this mainly due to the fact the PC stayed on the system Management/Restore page for several hours while I was gone.
Still may be heat, that's the easiest thing to fix. Open case, remove heatsink, clean cpu and gpu and replace heatsink with new thermal compound. You might be able to find a video on youtube about opening your case and the assembly/dis-assembly required.