Cleaned hard drive, reinstalled OSX- now all my iTunes purchased music is gone When I try to download already purchased songs I get this message:



Will I be charged once more if I click "Buy"?

Ps. When I click "Check for available downloads" I just get the message



Psps. It might just be that the new Itunes is buggy. I get this startup-screen, but when I click "scan for music", nothing happens.
Sign in to itunes, click iTunes Store. In the right hand column there is a link to "purchased"

 

This opens to a screen that looks like this:



You can re-download everything from there as long as its all on the single apple ID.

Good Luck!