Not sure what caused it, but last Friday night about 1/2 hour in to a 2 hour night cross country flight, my 740b froze.  I couldn't get it to respond to anything including restarting or power down.  I unplugged the power cord and waited for the internal battery to die, then powered it back up.
Has this happened to others in the past?  Was there a recent update that would have caused this?  Doesn't give me a warm, fuzzy feeling if this happens frequently.  Don't really like it if it happens even periodically.
JD