my treo 600 froze suddenly. The treo i have is an unlocked ATT Treo 600, operating with a TMobile SIM card. The Treo has suffered no falls or bumps, and had been in pefect working order within the prior 15 min. No new programs had been installed. The device would not turn off and exausted the battery nor would it respond to soft or hard resets. Please recommend what to do.