I installed Windows 8 CP. Since I installed it the computer will turn on and I can explor windows 8 for a brief period of time until it shuts down unexpectedly. It always starts back up normally, but will shut down again.

Does anyone have an idea where I can start looking to fix this issue?

This sounds like a corrupt installation. I might attempt a reinstallation. I would first download the iso file again (http://windows.microsoft.com/en-US/windows-8/iso). Then burn the iso file to DVD and use this DVD to Custom (Clean) install Win 8 CP again. This will give a pristine installation. I realize this will take a little longer, but most of the problems such as the one you have are caused by corruption of the installation and are most easily fixed by reinstallation.

It's customary, when posting a cry for help, that you tell us ALL about your PC. Make, Model, CPU, Age, amount of RAM, size of HD, etc.
Then we have something to go on, to try to answer your question.

Your problem could be anything from a corrupt install, previously mentioned, to bad ram, or even a dirty CPU heatsink and fan. (overheating)
Or possibly even errors on your hard drive.:confused:
If I had your PC on my repair bench, I would check all those hardware related things, before reinstalling the OS.

Most spontaneous shutdowns are caused by problems with the hardware, not software.
Even a low CMOS battery can cause weird problems, like shutdowns.

Good Luck,
TechnoMage :cool: