If nothing improves the frequency of the freezing, call in and tell them your DVR is freezing constantly, they'll send you out a replacement.
It could be possible that these are the beginning signs of a fatal error, and I wouldn't be surprised if in a week or so you boot it up and it says "a fatal error has occurred call cust service to report diagnostic code 24, 25, or 14.
All of which require a replacement. Essentially it's a storage failure that affects the whole operation of the receiver.