We have a three DirecTV TiVo units -- one is a Samsung SIR-4120R, another is a SIR S4040R and the third is the HR10-250. In the last couple of weeks my wife began experiencing problems with the 4120. Initially the problem was stuttering on programs being played back, and then it migrated to stuttering on live satellite TV as well. I spoke with DirecTV Customer Support who tried a few things, and after discussion of my home network, we discussed a few other options for me to try. I have an active multiswitch (Spaun), so after hanging up with DTV support I did some further testing. I moved the 4120 to another room (where the 4040R was -- which I disconnected temporarily) to let me confirm that it was neither the cable to the room where the 4120R was located nor the port on the multiswitch or the multiswtch itself. The 4120 had the same stuttering problem in the other room both on recorded and live programs. And all this time no problems on the other TiVO units. Next I thought I would do a full reset of the 4120. The DTV rep cautioned me that this could take a long time -- 3-4 hours. Well I started it last night around 9pm and it's now still going more than 12 hours later. In reviewing information on the web it appears that I may have experienced a failing hard disk on the 4120. And since the full reset is so far not finished, I'm guessing I need to put in a new hard disk. Three questions: 1) Does my analysis seem reasonable? 2) What happens if I interrupt the full reset with a power off/on sequence? 3) If my analysis is reasonable, can I backup/copy the disk in the 4040R to a new disk and use it in the 4120, or do I need to order a replacement hard disk for the 4120 from someone like weaknees because the 4120R config is different? Thanks in advance!