That's a known problem.
See if http://benosullivan.co.uk/windows/fix-high-cpu-usage-audiodg-exe-in-windows-7-and-vista/ or http://technicallyeasy.net/2009/03/fix-audiodgexe-high-cpu-usage/ help.
I was quietly playing Solitaire, when NIS 2011 Insight Protection popped up a message naming Audiodg.exe and letting me know CPU usage was at least 89%.....at the very least, my heartbeat must have increased more than 89%. Disappointed I am!!.... I was sure my powerful computer would rise above such messages
XPS 8100 64-bit
Intel Core i7-870processor (8MB Cache, 2.93GHz)
8G Dual Channel DDR3 SDRAM at 1333MHz-4 DIMMs
Too many processes running in Task Manager, I suppose -- I might have to give up Solitaire