Alec Mowat said:
Sounds like a dying powersupply.
Only way to be sure is replace the PSU and test it again.
Powering on and off doesn't sound like an OS issue. It's possible that the PSU was on it's way out, and doing the install drew enough power from the system to finally kill it.
Thank you for the advice.
EDIT: I replaced the power supply but the problem is still going on. I'm sending the system off to a service center and hoping they can figure out what's wrong with it. I'm out of ideas.