I have a 20 gig click wheel 4th generation. When I try to turn it on the Apple logo comes on and you can here a faint whine as it tries to boot up, but then there is a clicking sound and it stops. Then it tries again, there is a click and it tries again. Ultimately it displays a support web address. I really like this iPod and would like to keep it. What is the most cost effective way to repair it? Thank you!