How to fix a broken i pod
it turns on but it freezes all the time
You can try resetting first your iPod. Instructions here http://support.apple.com/kb/HT1320. Just click on the specific iPod you have and follow instructions.
take it to an apple store and for $100 they will exchange it and give you a new one
Try holding the lock button and home screen button for about a minute. This is info for iPod Touch