HP iPAQ 310 hard reset

HP iPAQ 310 Soft reset

Use the RESET button (4) to reset the Travel Companion.

HP iPAQ 310 hard reset

Push the scroll wheel and RESET at the same time, then release RESET button. Keep pushing scroll wheel button for a while.

Scroll down to 10. then push the scroll wheel.
Never choose 11. without any backup of your FULL ROM file!!!