Black Screen Crash

Specs:
Intel i7 2700k
ASUS Sabertooth Z77 MOBO
Sapphire 7970 3GB GPU
Corsair TX 750 PSU
Old RAM from a Gateway 860 FX

Hi, I hope everyone has had a fun- and safe- holiday season! Alright, so I have recently been experiencing a problem with black screen crashes PRIMARILY during gaming (it has happened once during browsing). The monitor says "no signal", the GPU fans speed up and I'm forced to hard-restart. I have reseated the GPU several times in both PCI-e slots and the same thing happens. Here's one thing I haven't been able to find any help with on the internet: it tends to do this when the GPU is wiggled a tiny bit. I figured this out when my brother dropped a weight and my computer black-screen crashed; I replicated this by wiggling the card. It happens a lot easier while playing games. I ran a furmark test and it went to 75% before the screen went black, but it did not crash. I hard-restarted it at that point. GPU temps went to about 72C max. Due to the wiggling, I'm thinking it's a GPU issue. I've had this setup since last month, and only the past couple days has it been giving me issues. Any help would be greatly appreciated!