So basically, I have a 2GB VTX Radeon HD 7870 and occasionally it would produce horizontal lines on my monitor. These lines were so thick that I couldnt see past them so I'm forced to hard reset the PC. If I have music playing and I get these lines, I can still hear the music. These lines never happen when I game. Their random, sometimes when Im on Youtube, sometimes when I'm editing. I didnt know it was my graphics card so I took it out, removed all drivers etc and I havent had a single problem with the Intel 4000 gpu. I know it is the Radeon but I dont know why its happening? The temperatures are fine, idle was around 27 - 35 and gaming was around 50 - 70. The card is stock and I havent OC'd or made any changes to it. My spec is a 3750k i5 cpu, 750Watt PSU, 8GB DDR3 Ram, 1TB Hardrive, Gigabyte Z77-D3H. Please help me. Thank you guys!