I was able to fix this problem on my new THR-22. The drive is now considerably quieter. I can still hear some hard drive seeking, but it is much less noticeable. The problem is that the hard drive is attached in a hard plastic case and screwed directly to the motherboard in two places, and the metal case frame in two places, with no insulating material of any kind. In contrast, my Series 2 Tivos, which are much quieter, have nice rubber anti-vibration bumpers to isolate the drive. All I did was to place some #5 O-rings that I bought in the plumbing department of Lowes between the plastic case and each mount point. Actually I was only able to fit the O-ring under one of the frame mount points, because there is a pretty tight fit and I did not want to push hard on the case. These rings are only 1/16th inch thick; don't bother trying anything thicker. So now the drive case is attached at 3 points, and there is a small gap at the other mount point so that there is no direct contact of case to frame. This is pretty easy to do as long as you have the T-7 star torx screwdriver to get in the case.