Try to get it going with a hard reset. Remember that it WILL ERASE YOUR DATA

The iPAQ can be HARD RESET by doing the following:

1. Press and hold application buttons 1 & 4 (the Calendar and iTask buttons respectively, shown in the diagram below) on the front of the unit while simultaneously pressing the reset button on the back of the iPAQ with the tip of your stylus.

2. Keep all three buttons depressed until the image on the screen fades, which should happen within five seconds.

3. Release all buttons.

4. To confirm that your HARD RESET has completed, press the power button. If the HARD RESET has completed, the power button will NOT power the unit back on.

5. To reactivate the unit, connect it to AC Power or press the reset button on the back of the unit.

There is more info here and here as well Good Luck and I hope it works for you.