Strange really, how some don't have issues with nvidia drivers and some do.
This happened with Nvidia some time back with a fan issue, some people had their nvidia fan stopped working, some didn't work propely and others worked fine. All through a Nvidia update
GeForce 320.49 Driver BETA is on the main Nvidia website now, seems a WHQL might be added over the next couple of days. Hopefully that will fix the weird problems people are getting. Until then it may be worth sticking with 314.22..
WHQL is just a microsoft stamp of approval, there is every chance the same issue will show up