What do you do if your itouch won't turn on even though it's charged?

Try putting it into DFU mode. To do that,

1.Open iTunes and connect the iphone to your Mac.

2.Press and hold the Home button and the Sleep/Wake button at the same time.

3.After exactly 10 seconds release the Sleep/Wake button.

4.Continue holding the home button until you iTunes pops up a message telling you that it has detected an iphone in recovery mode.

5.Then unplug your iphone and wait for it to shut off. After that turn it back on and it should be back to normal.