I have a 460 as well and I had this problem a couple of months ago.
I know I went back to older drivers after it happened, then I think I updated them late this winter, and I haven't had a problem since.
I remember at the time I was having a lot of problems with the card I had some HDD problems as well and once I sorted those out and changed my drivers everything was fine.
EDIT: I'm on 306.97 right now.
Last edited by StealingYerMail; 06-06-2013 at 07:54 PM.