iTunes won't open

iTunes won't open. It was fine a few days ago -- managed my playlists, etc., but now, when I press the iTunes icon, it just bumps up and down a few times, and then stops. I've already checked Force Quit -- it's not running -- and I've done a total shutdown / power off reboot a number of times. Nothing doing. (Help? I can't clean my kitchen without Aretha Franklin!)

(FYI -- I have a vintage MacBook running on 10.6.8, so I can't download the latest version of iTunes -- but that didn't seem to be a problem a few days ago when I was buying and downloading new tunes from the iTunes store and adding them to my playlists.