In order to hard reset a Palm Treo 500v, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Palm Treo 500v device will be brought back to the default configuration of a brand new device.
1. Remove the battery.
2. Press-hold Power button. Put the battery back in.
3. Let go of Power button when the Palm logo appears on-screen.
4. Press Up to accept the "Erase all data?" message.
5. Select the language you want with OK.
6. Done.