Toshiba (Audiovox) PDA Genio e550c

Always start with the simplest answer first, so start by removing any memory cards, attached devices and cables and resetting it again.
If you still have the same problem check the manual for the Hard Reset procedure, it may seem you've already hard reset it by killing your battery but it's worth a try anyway when your getting this kind of issue.

Same problem, except some moisture squeezed into the digitizer (or touch screen) and rendered it inoperable. Have not found a place to get another digitizer.