screen goes black
Newest Mac Mini, My screen will randomly go black for several seconds and return without my doing anything to get it back. It happens while workin in various programs, browsing, etc. The computer is set to require a password on return from sleep but when these events occur the display returns to whatever I was doing, no login required. Everything is up to date. Any suggestions or help would be appreciated.
MacBook, Mac OS X (10.7)