Random black boxes, flickering, and glitchy screen on applications

[HALPmehplz]

Hello, can someone please help me with a problem I am having? I have a nice custom PC that I built about half a year ago. It has been working perfectly fine since, however recently about 2 days ago, I have started to get strange "black boxes" appear on screen and flickering text, etc. in applications such as CS:GO, Google Chrome, and all other browsers, games, etc. even microsoft word! These are my specs. And I have included some screenshots as well.
SPECS:
Processor: AMD FX-8320E Vishera Black Edition
Graphics Card: SAPPHIRE Tri-X AMD Radeon R9 290
RAM/Memory: DDR3 8GB Dual Channel RIP JAWS
Motherboard: GIGABYTE 990FXA-UD3
H800i Water Cooler

SCREENSHOTS:
>URL BAR http://prntscr.com/8stn67
>CS:GO GAME CONSOLE TEXT http://prntscr.com/8sto17
>CS:GO LIGHTING GLITCH AND BLACK BOXES http://prntscr.com/8stodb

 

[COLGeek]

What make/model PSU are you using? Are you OCing anything (CPU, GPU, memory)? Are Windows, your major drivers, and your motherboard BIOS up to date? What are your CPU and GPU operating temperatures at idle and under load?