I've been having this problem lately with my AppleTV. Every time I go to use it after it's been idle for a few hours, it appears to have reset itself. The menu will be at the top level with the "Top Movies" thumbnails in the background instead of at the last place I left it. Then, when I go to my "Shared Movies" or "Shared TV Shows", AppleTV says that I have no files in those libraries. After going back and forth between the two a couple of times to force them to load, the AppleTV will stall for a moment with the name of my streaming computer as the only selection, then finally it will load my shared libraries. Most of the time it will operate normally after this point, but sometimes it freezes during streaming making me wait a very long time before it resumes. If I get too impatient to wait for that and give up, when I come back to it it has reset itself again. I'm using version 2.3 of the software and I'm streaming over ethernet. I should also say that I installed Boxee at one point but decided to factory restore.