I have a Hughes DVR40 Series 2 DirecTV Tivo that is on its 3rd HDD. I have been running on a Samsung Spinpoint 160G for the last 6 years. Recently I have gotten a lot of odd behavior, different from past HDD failurs. It started with me receiving several messages from DirecTV that I needed to activate my DVR. Then I stated to get stuttering and some pixellation of the picture when watching live video. Now, when I am using the guide, it will suddenly disappear from the screen as if I dismissed it. That also happens with the info screen. I am also unable to enter my security code to unlock "content blocked" video. When I select a "content blocked" recording in the "Now Playing" list, the password screen pops up, and then immediately goes away before I can enter any numbers. In addition, I am also getting occasional invalid access card errors. When I run a systems test, the signal strength on both tuners is in the mid 90's. The access card sometimes passes and sometimes fails. Recorded video that is not content blocked, seems to play OK, i.e. without any skipping or pixellation. Another odd thing is that if I unplug the unit for a few hours and plug it back in, I get no lights, and no video output for a few minutes. It sounds like the HDD spins up, but I get no indication of any activity. After a few minutes, I will get the green and red lights on the front panel flash alternately, and finally the green light will come on solid and I'll get the "Powering up" messages. From this point it will progress normally up to the acquiring satellite info screen. Then about half of the time it will reboot before the process completes. It then usually finishes correctly the second time. So my question is, are these symptoms consistent with an HDD failure, or am I having some other problem, like a power supply or main board problem?