First of all, welcome to LQ and the wonderful world that is Linux.
I'm just taking a wild guess here, as you have described quite a bit, but not necessarily the pertinent pieces (no worries, we'll ask if we need them). When you set up your nvidia card, did you set it up with the rpmfusion repo or did you compile it? If you compiled it, then you will need to recompile it for the new kernel and every new kernel you get (the come out fairly often). If you installed it from the rpmfusion repo, then this is not likely the problem and we need some more info. If you didn't install it from rpmfusion, then you may prefer to do so. It can be done by installing the rpm's listed at their site
and then running the command:
yum -y install kmod-nvidia
Let us know if this fixes things or not,