According to the Palm support website, as of September 2010 there are five Treo models: the 600, 650 and 680, as well as the 700p and 755p. Most of the models have a similar hard reset process involving removing the phone's battery and following on-screen prompts. Each Treo's hard reset yields the same outcome: a complete system wipe and factory default restoration. As the support website says, "don't perform a hard reset unless you've backed up your data, or you're willing to lose everything."
Instructions
Treo 755p, 700p and 650
1. Disconnect your Treo from its power source.
2. Unplug the Treo's USB sync cable.
3. Remove the battery cover from the back of the smartphone.
4. Take out the battery.
5. Press and hold down the "Power/End" button on the keypad.
6. Put the battery back into the smartphone while still depressing the "Power/End" key.
7. Let go of the "Power/End" button when the following logo appears on the smartphone's display--the logo for the Treo 755p will read "Palm OS. Powered by Access," the Treo 700p will read "Access Powered" and the 650 Treo display will read "Palm Powered."
8. Press the "Up" arrow key when "Erase All Data?" displays on the Treo's screen. This completes the reset procedure.
Treo 680
9. Disconnect your Treo from its power source.
10. Unplug the Treo's USB sync cable.
11. Remove the battery cover from the back of the smartphone.
12. Remove the battery from the battery bay.
13. Replace the battery.
14. Press and hold the "Power/End" button when the "Palm" logo appears on the display.
15. Continue to hold the "Power/End" button until an "Erase All Data?" prompt appears.
16. Press "Up" to confirm.
Treo 600
17.Unscrew the tip of the stylus to uncover the reset tool.
18. Press and hold down the "Wireless Mode" button.
19. Press the "Reset" button on the back of the Treo with the reset tool while still holding down the "Wireless Mode" button.
20. Release the "Wireless Mode" button when the "Palm Powered" logo appears on the device's display.
21. Press the "Up" arrow when "Erase All Data?" appears on the screen.
Tags: Power button, button when, Erase Data, hard reset, logo appears, Mode button