Also, check the hard drive counters (Menu-6-3-Counters) and report the HDD temperatures. A high of around 140 and an average of over 130 will cause problems.
Like I said, the 722K has already been replaced (again). I tend to believe it was the hard drive. FYI, the 722K wasn't inside an enclosure or otherwise subject to elevated temperature. But next time this happens, I'll check the hard drive counters.
