What process are you following when attempting to do a hard reset?
It looks like the official process, at least per Spring, is to:
!. Power the device off
2. Press and hold the "R" key
3. Press and hold the "M" key
4. Press and hold the power button
5. While continuing to hold the three listed buttons, wait till a triangle is displayed on screen. Then release all three buttons and then press the "@" key.
6. You should now see a menu displayed.
7. Use the volume down to scroll to "wipe data/factory reset".
8. With "wipe data/factory reset" highlighted, press the return key.
9. Another menu should now be displayed, use the volume down to scroll to and highlight "YES".
10. Press the return key to perform the reset
Perform a hardware factory reset - Motorola XPRT