If holding the red power button doesn't start the Imagio, see if you can get into the bootloader (press the volume down button and then press the red power button, keep both pressed until you get a tri-color screen). If you see the bootloader screen, you should be able to connect the Imagio to a USB port on your PC and reinstall the Imagio ROM from
Personal Communications Devices | Our Devices - XV6975. Hope that works.