So basically, my computer only crashes when i play fortnite. When it crashes, all it does it it freezes to whatever frame i was in, and i can't do anything except hold the power button and restart it. I've tried waiting to see if it unfreezes, but after 30 mins i just restarted it.
It ONLY crashes if i'm playing fortnite or if i have fortnite opened. Any help would be great. Thank you!

Get SPECCY here: http://www.piriform.com/speccy/download
...get the FREE version from either link listed.
...Speccy is a really nice system hardware/temperature, information Utility.
...simply install it...and run the program...then post a screen shot of the main page of the program, when posting a problem/question on these forums.

disable any oc and redo drivers.
when you freeze do you still continue to hear sound?
is there any BSOD mini dumps?

I mean you could sotp playing Fortnite

J/k

Is it a system crash or a application crash?

system

What happens if you run a stress test like aida 64 or prime95? (Run aida first, prime is much harder on cpu).
What are you temps while gaming?

You aren't loading any sort of game hack are you (even if it's for another game)?
You also don't have a reverse engineering tool or debugger open in the background, right?

PB and other anti-hacking tools will false-positive flag you for that and seize your system (potentially).