HP iPAQ rx1900 Supplementary Manual page 14

Locking and Unlocking the Today Screen
To prevent accidental screen taps when you are not using your HP iPAQ,
you can lock the Today screen so that taps are not recognized.
To lock the Today screen, tap the Open Lock icon. The icon changes
to the Closed Lock icon and the screen is locked.
To unlock the Today screen:
1.
Tap the Unlock soft key at the lower left of the screen.
2.
When the Unlock screen is displayed, tap the Unlock button.
The Today screen is displayed and unlocked.
3