ipad 2 won't turn on

Try a reset. Hold the Sleep and Home button down (together) for about 10 seconds until you see the Apple logo. Ignore the red slider.

Note: For a reset to be successful, you must see the Apple logo.

If the hard reset didn't produce an apple logo; and the device isn't showing up in iTunes; there is a chance the hardware may need service.

Try doing a hard reset on the phone;

1. Hold Home and Sleep/Wake buttons at the same time;

2. Wait for the Apple logo to appear

3. Let go of the buttons when you see Apple on the screen

iTunes doesn't recognize the device

Have you tried different usb ports on the computer? or a different cord possibly?

Also see the below articles:

For Mac: http://support.apple.com/kb/HT1747

For PC: http://support.apple.com/kb/HT1923