[SOLVED] Computer tuns off after a couple of hours of usage. The parts are all brand new. I have read that it could be PSU issue. I am currently using a CX500

Solution
Certainly, when a rig develops as issue of just instantly shutting off, a PSU is often a prime potential culprit...

But, given the other facts give, (i.e, none), you are not likely to get much more than a 'maybe' on assistance.

Have you monitored 'under load' CPU temps/clock speeds, to rule out potential overheating issues? (Some motherboards maybe have BIOS settings to induce hard power off at certain temp conditions..)
Certainly, when a rig develops as issue of just instantly shutting off, a PSU is often a prime potential culprit...

But, given the other facts give, (i.e, none), you are not likely to get much more than a 'maybe' on assistance.

Have you monitored 'under load' CPU temps/clock speeds, to rule out potential overheating issues? (Some motherboards maybe have BIOS settings to induce hard power off at certain temp conditions..)
 
Solution

King_V

Illustrious
Ambassador
Given that the wattage ends in 00 rather than 50, I'm guessing this is an older CX unit... which, even though your system isn't placing a huge demand on it, makes me suspicious. The modern (2017) CX units, while not spectacular, are better.

It may not be the power supply causing it, but I would replace it anyway. See the first link in my sig for recommendations.