Program Guide Self Starts

DVR or STB model being used? IPG being used?

When you say TV guide, do you mean the box's guide? Like what you get when you press guide on the remote? Just making sure you don't mean the "TV Guide" channel.

First thing that comes to mind is the guide button is broken/stuck on the remote/box. Also try putting something on front of the box like a book (something the remote signal cant get through) and see if it happens. If it does, then you have isolated to a box hardware problem.