DVR Recording Error and On Demand

Hello, I am having two reoccurring errors that have been going on for a little over a month now. 1) When I play a recorded show on my DVR it only plays for a second or two and then gives me an error and stops. Additionally, the recording light will remain lite throughout the time selected for recording but when the recording is started it will only show 15 minutes have been recorded but still only plays for a second. -Another issue for some recordings is that it pauses and is choppy throughout the recording. 2) I can see a show that is lists as ON DEMAND but when I select the show to play the screen goes blank like it is trying to load it and then after about 2 minutes it goes back to the ON DEMAND title screen where you can select a specific category. Even from that screen I can look up the name of a show but it won't load. I only have one DVR that is directly connected to the cable, I have checked the connection to the DVR and the TV, and I have reset my receiver multiple times (an had the receiver reset on its own). Currently my DVR is showing 45% full on the hard drive.