I've had this happen as well. It's been a while, but what I seem to remember doing was, withe the batteries in and the unit ON pressing the menu key and then the power key and unit turns off. Hope that works, TT.
Uniden 396XT, PSR-800 x2 , PSR-500, BC 250D, BC 245XLT, YAESU FRG-8800. Using Freescan and PSREdit500.