Think my GPU is on the fritz?

So the last couple of weeks I have noticed that if I move the mini HDMI cable connected to my GTX 460 then I get green lines on my display just like you do when the cards ram goes bad. All it takes just a small bit of movement and the screen is back to normal. I can game on the card and using MSI After Burner I can get a pretty decent STABLE OC aswell. Now just tonight I tried to load up MSI After Burner and I get an error message

"msi afterburner failed to load rtcore64.sys driver"

I also tried to load up GPUz and I get this

"gpu z could not start driver a device attached to this system is not functioning"

I tried to reinstall the Nvidia drivers but I also get an error doing that

Help Please

 

Make sure the card is still securely seated in it's slot.