Reset the Sony Pocket Reader by pressing the "Reset" button on the back with a small pin or paperclip. Turn the "Power" switch to turn on the Reader. This will not affect the content that is stored on the device. If you connect it to your computer before turning it on, the computer will not recognize it.
Give the reader enough time to charge fully, if the battery life is short. You may need to replace the battery if the problem persists. To do this contact the nearest Sony Service Center. If it has been a long time since you've charged the reader, it will take repeated charging to charge it completely.
Wait a few hours if the reader will not turn on. If any moisture or condensation has gotten into it, it will likely work after you give it time to dry out.
Check that the device lock is not turned on, if you are having problems with your computer recognizing the reader. Verify the "indicating connection via USB" is displayed at the top of the reader's screen. If it is not, disconnect the USB cable, wait a few minutes, and then reconnect it.