When on my custom PC, I frequently experience freezes that cause me to force shut down my PC. These freezes usually occur while playing games, but also happen sometimes while browsing the web and watching YouTube. At first, I thought it was a GPU thing, but then I ran Valley Benchmarks for an hour with no freeze. Normally when I play games, it takes 5-10 minutes to freeze. I've checked both my HDD and SSD, and neither of them have problems. I've checked the voltage rails in the BIOS, and they seem normal. I've tried installing the newest versions of graphics drivers, including betas. I've also tried old versions, and still no solution. Besides those, all my drivers are up to date.
Here is my rig-
Intel i7-4770k
EVGA Geforce GTX 770 Superclocked 2gb Vram
Crucial Ballistix Sport 8gb DDR3 1600 (1 x 8)
Asus Z87 Pro Motherboard
Corsair CX750 PSU
Western Digital green 2TB HDD
Samsung 840 Evo 120GB SSD
Windows 8.1 64 Bit
Here is my rig-
Intel i7-4770k
EVGA Geforce GTX 770 Superclocked 2gb Vram
Crucial Ballistix Sport 8gb DDR3 1600 (1 x 8)
Asus Z87 Pro Motherboard
Corsair CX750 PSU
Western Digital green 2TB HDD
Samsung 840 Evo 120GB SSD
Windows 8.1 64 Bit