video card

I have a Dell 8700 that is now off warranty. Right before the warranty expired Dell replaced both the motherboard and the Nvidia GeForce GT 635 card. My problems are now back full force once again, only worse. The screen keeps freezing, sometimes it goes black and then comes back ... and sometimes I need to do a hard boot to start over. This happens frequently in my day. Nvidia says to update the bios, but I'm not sure that is something a novice should do. They claim it is not on their end. So how do I fix this or do I just learn my lesson and pull this dang card out and replace it?