Well I have had this many times with the XFX Radeon 5850 I had (later found out the crossfire did not work too well), but i'm 100% it was the drivers for the card since I later REFORMATTED my PC and I still got them sometimes, (where the screen goes black and you get the noti. that the driver crashed [lol])
But on this 580 im running, never had a driver problem... yet. Pretty sure its the drivers though, check for more recent drivers if any.