I have recently had a spate of problems, which all arose after the battery died once (when I forgot to charge it). These include lack of sound, complete non-functionality of some apps (e.g. media player, camera), internet no longer working (except for Skype, oddly), and finally (this morning), the touchscreen stopped responding (when my alarm went off). Devel enabled, and CSSU installed. Time for a reflash I guess.