I have the 3510 and lately the box becomes very unresponsive while recording shows and sometimes when not recording. I would try the usual unplug/reset routine but due to the fact it is recording I can not do this reset of the box. I can get the guide to come up after a number of tries but it will not change pages and will not exit out of the menu on occasion. The box will not change channels either through the guide or channel up/down buttons on the remote. I have shut off all sources of possible interference ie lights, curtains/blinds with no help. Anyone else having this issue figure out a solution?