I recently decided to upgrade my PC. Did my research and ordered the parts (Everything but the PSU, RAM and a secondary hard drive were brand new). After trying it out for a bit, I ran into a complete system freeze during gameplay (Nothing too fancy, just Mirror's edge on high graphics). After restarting the system the same happened during a YouTube video, but this time the PC couldn't restart and had several strange colors and shapes during boot-up, including large squares and horizontal lines. It booted, but around the point where the windows loading screen should've been, it rebooted again in an endless loop. Starting the PC in safe mode would get me to the desktop, but the screen was filled with horizontal lines which would disappear as if being erased in MS paint if I moved anything such as the mouse cursor over them. After disappearing, they'd just reappear somewhere else on the screen. The PC worked perfectly with an older GPU (Which I'm using now), so I sent the new one in for repairs.
Now, it's on it's way back, and I just want to be sure that it won't just blow up again when I put it back in. Any help as to how to make sure it won't happen again or what the weird lines mean or how a GPU managed to prevent the PC from booting would be much appreciated. I think the company I bought it from might get a little curious if I send the same product back twice in a short period of time.
GPU: GTX 780 (Blew up. Currently using Radeon HD 4850 as a replacement)
CPU: AMD FX-8320
Mobo: Asus M5A97 LE R2.0
RAM: A single Kingston 8Gb HyperX Blu, 1600MHz DDR3
PSU: SilverStone STT-ST70F-ES (700W)
Thanks in advance,