Shutdown and flicker

I just built my computer the other day and i have been having some problems with it that are really starting to bother me. There is a flicker that the screen does but only on the desktop window or when playing league of legends. Another problem is that the computer wont turn off after i tell it to shut down. It runs the shutdown fine and the monitor says no signal after but the fans and lights all stay on. Here are the specs on my computer.

ASUS P8Z77-V LK LGA 1155 Intel Z77 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard with UEFI BIOS

CORSAIR Enthusiast Series TX650 V2 650W ATX12V v2.31/ EPS12V v2.92 80 PLUS BRONZE Certified Active PFC High Performance

Intel Core i7-3770K Ivy Bridge 3.5GHz (3.9GHz Turbo) LGA 1155 77W Quad-Core Desktop Processor Intel HD Graphics

G.SKILL Ripjaws X Series 8GB 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL10S-8GBXL

XFX Double D FX-787A-CDBC Radeon HD 7870 GHz Edition Black Edition 2GB 256-bit GDDR5 PCI Express 3.0 x16 HDCP Ready

Please someone get back to me as soon as possible. I have had this for two weeks now and i would like to see if i could solve it without sending stuff back unless i have to. I have made sure everything was up to date i have tried to isolate the problem but nothing has worked.