Multiple Graphics Drivers?

Hello,

Recently I sent my EVGA Geforce GTX 560 ti 448 core Graphics card away for RMA.
I did not uninstall the drivers as i was expecting the same card back, however they had none in stock and instead sent me a EVGA Geforce GTX 570.

I proceeded to install that, but cant figure out how to uninstall my old gpu drivers. I tried using device manager but it only shows my GTX 570.

Could this be causing problems??

I'm still having my computer hard freeze during games, although there is no longer a looping sound as there was with my old card.
I was almost certain a new card would fix the problem, as i installed my friends GPU correctly after uninstalling my old one to test, and all worked perfectly.

Any help will be greatly appreciated.