HP IPAQ 4150 not turing off

I recently installed TomTom 3 and I have noticed that ocassionally when I turn it off the screen goes black (not off just black) and the the bluetooth is still flashing

Has anyone else come across this? I notice it mainly in the dark when I turn it off as the screen although black still glows and bluetooth is flashing (if on)

Any suggestion would be good as I need to keep hit reset to be able to turn it off fully.

Thanks
Simon

[Charlie]

You may be turning the backlight off instead of the PDA. Press the power button quickly to turn the PDA on/off and press and hold the power button slightly to turn the backlight on/off.