computer is freezing red screening and flickering a black screen all the time

[Roddels]

i am new to this site so sorry for any lack of detail
i got a decently expensive gaming pc and i want to know how o fix it without having to go in and pay even more for it and i have tried everything i can think of and i haven't found any sites with this sort of mix of problems
specs are
Operating System
Windows 8.1 Pro 64-bit
CPU
AMD FX-8350 41 °C
Vishera 32nm Technology
RAM
16.0GB Dual-Channel DDR3 @ 722MHz (9-9-9-24)
Motherboard
ASUSTeK COMPUTER INC. M5A99X EVO R2.0 (Socket 942) 34 °C
Graphics
ASUS VS247 (1920x1080@60Hz)
2048MB ATI AMD Radeon HD 7800 Series (MSI) 37 °C
2048MB ATI AMD Radeon HD 7800 Series (MSI)
CrossFire Disabled
Storage
111GB KINGSTON SV300S37A120G (SSD) 34 °C
2794GB TOSHIBA DT01ACA300 (SATA) 35 °C
Optical Drives
HL-DT-ST BDDVDRW CH12LS28
Audio
AMD High Definition Audio Device

 

[maikutech]

Can you provide the psu details please, also I want you to remove one of your 7800 cards.
Test it for 5 to 10 minutes and see if windows may rsod or bsod you, that way you'll know which one is defective.