The iPod model number A1099 refers to several variations of Apple's portable media player -- two versions of the iPod photo, the iPod with colour display and a special U2 product. These fourth generation devices vary slightly in terms of size, specifications and software but function in a similar way. They were the first iPods to display photos -- though not video -- and were therefore an important step in the line's transition from purely a music product to a fully-fledged media player.
Plug your iPod into a power socket using the supplied adaptor.
Slide the "Hold" switch on the top of your iPod on and then off again.
Push down the "Select" button in the centre of the click wheel and the "Menu" button above it at the same time and hold them for more than six seconds -- don't let go until the Apple logo appears on the screen. The software then runs through the reset process and, with luck, the problem is solved. Resetting should quickly fix most problems.
Check that the "Hold" switch is in the off position.
Ensure that the "Hold" switch on the optional remote control is turned off as well.
Connect your iPod to a power socket using the adaptor -- it could just be that the battery has run down.
Download the most recent version of iTunes onto your computer.
Launch iTunes and hook your iPod up to your computer.
Choose your iPod in the "Source" list, click on the "Summary" tab and select "Check for Update." If a new version is available it will load onto your iPod -- you should always run the latest version.
Make sure that any files stored on our iPod in disk mode are backed up -- restoring the software wipes everything off the hard disk. Music is stored on your computer using iTunes, so you'll be able to reload it after the process is complete.
Follow the procedure at the start of Step 3, above, and when the summary tab appears, select "Restore." You will be presented with a number of options -- choose numbers three or four to load the most recent software version.
Follow the on-screen instructions to complete the restore procedure. The steps you take vary depending on whether you are using a PC or a Mac.
Other fixes include using a different USB or FireWire port when you connect your iPod to your computer, restarting the computer and uninstalling iTunes and reinstalling the latest version.
Never try to open the case and carry out repairs inside as you could receive an electric shock. Only use the adaptor that came with your iPod, as other chargers could damage the device.