Try a factory reset and then start over.
With the 721, unplug it and open the case. Remove the ribbon cable from the hard drive, plug it back in and watch what happens. It will attempt to find the hard drive and eventually give youqa message that the HD canot be found (I can't remember how long the process takes, but you need to wait for that message). Unplug it and replace the ribbon cable on the HD, plug it back in and power it on. It will recogize the HD, reformat, repartition and download new operating software. I did this with mine last year and it has worked like a charm since then.hometheaterman said:Yeah thats why I figured I minus well get the 722 I wanted since they all have a DVR fee. I am putting it in single mode like you said as I only want to power my 1 tv with it and want to be able to record 2 things at once. The only thing I'm worried about is I've read about some bugs where it's not skipping all over the place when you try to fast foward or rewind and then hit play. That would be really annoying as I like to skip commercials.