Odd CPU Usage Graphs with Blackscreens

[Fury_ZA]

Hi

My PC started going haywire recently and I'm starting to troubleshoot to find the problem.

Usually what happens is I play a custom Dota 2 Game and after about 4 minutes my screen goes black, gpu fans go to 100% and the background music still plays.

I just updated the BIOS of my motherboard so I haven't tested it yet.

 

I've also noticed an irregularity when I did a Furmark burn-in test.

Have a Look

 

My PC specs are as follows :

 

Intel DH77KC LGA 1155 Motherboard

Intel Core i5-3570

8 Gb of mishmash ram (4gb+2gb+2gb)

MSi GTX 760 (Not overclocked)

700watt Rex PSU (Might be dodgy, had the thing for 3 years now)

500gb Seagate Harddrive (Last format was about a year ago, need to replace)

 

Thanks for reading 

Fury