Sound like it is going into sleep mode., and not waking up properly. I have had the same problem in the past. In the BIOS there is a energy managment settings S1, S3, S5. And some thimes timmers for HD and video. Turn off when you find it. Windows is controlling the same hardware in the Screen Saver/Energy Settings.
Check to see what windows settings are set too. The default setting are Home/Office with 15-20 min timers.