If it is after an hour it could be to do with the laptop over heating. You can force it to come sooner by running a load testing. This should force it to happen sooner.
The blog below suggest a load testing tool. If it does turn off quicker than the hour, it most likely is the temprture.
A possible cause to the laptop over heating is that a laptop is being used as a laptop should be on your lap. The only problem is that it pulls all of the dust in with it. I would recommend that you vacume the laptop and focus on the air output and input areas.
There is also a tool on that blog for system specification, it has a section that will show the current temp of the CPU.
Answers & Comments
If it is after an hour it could be to do with the laptop over heating. You can force it to come sooner by running a load testing. This should force it to happen sooner.
The blog below suggest a load testing tool. If it does turn off quicker than the hour, it most likely is the temprture.
http://simontodd.com/2010/01/how-prove-that-your-computer-has-a-hardware-fault-load-testing/
A possible cause to the laptop over heating is that a laptop is being used as a laptop should be on your lap. The only problem is that it pulls all of the dust in with it. I would recommend that you vacume the laptop and focus on the air output and input areas.
There is also a tool on that blog for system specification, it has a section that will show the current temp of the CPU.
Thanks