T-Mobile MDA III - Manual (Page 162)

T-Mobile MDA III User Manual 162
default settings. Programs installed at the factory remain,
erasing all data that you have created and programs you
have installed.
Press and hold the
power button, and then use the stylus to
press the soft reset button at the same time. Be sure you
have backed up all your data in a SD card or on your PC
before performing a full reset.