Hi everyone I'm hoping I can find a solution on this site because I don't want to buy a whole new computer. My problem is that my PC will crash to a random solid color such as beige or grey. This started 3 days ago when I was PLAYING csgo with my friends and it happened once. I thought it was just like a BSOD and I rebooted my PC and everything was good for 3 days. Then all of a sudden my PC would crash to these solid colours frequently and eventually to a point where I can't even start up a game because it will just crash instantly. During these crashes I'm SOMETIMES able to hear sound and other times I'm not. It crashes every 30 MINS to an hour when I'm not gaming. My dad and I built this PC 2 years ago and I have NEVER experienced any issues with it. All of a sudden with no warnings of symptoms my PC would crash. Sometimes my PC won't even start up and my screen will flicker black after I get to the login screen.

My specs
Amd EIGHT core fx 8320
Windows 7 service pack 1 64bit
Amd Radeon r9 280x visiontek/msi
Psu corsair cx750m
Gigabyte motherboard model 990fxa-ud3
Dual 4g memory corsair vengeance

What I have tried to do
-updated graphics drivers to latest version
-started a system repair
-used safe mode
-fan Intel test for cpu with no issues
-ran FUR mark Gpu test and my PC instantly crashes (tried 3 times)
-did an anti virus scan and no issues here

Help will be appreciated but u believe there is a problem with my Gpu due to the fact my system crashes during furmark


Notes: my PC crashed 3 times while writing this so I used my phone to write this all out

Thanks for future replies