I'm having trouble with my wireless computer thingy too and did a quick search and found this thread. Maybe it is just batteries? It has been pretty cold around here lately (right around freezing). I did work for a couple of seconds when I was on the train home the other day, but hasn't worked since. The display lights up and shows time and the stopwatch works, but it's not sensing anything from the little sender so I don't get distance or speed. Somebody mentioned magnetism....could it have anything to do with the train? (I commute most of the way to work by train, then ride the last 3 miles). Or is it just batteries dieing? I'll try getting new batteries this week-end.