As in it doesn’t work at all or just in some screens?
Check the Notification Center (long press of power button), there is a control to enable or disable touch (icon of finger tapping screen). Maybe you accidentally disabled touch via that control.
Don't know anything about H1i. But it's typical of the touch devices like the 7x0i to have a way to lock the screen. Prevents accidental functions while in your pocket or pack. Or even on a lanyard.
