iTunes kept freezing and now it won't start at all

It all started when I downloaded an iTune U class that contained a lot of videos and chose to download all old episodes. It turned out there so many that it would take 25 hours. I tried to abort the downloads, but apparently that messed something up.

First iTunes started up normally, tried to download "83 items" and then started to freeze up after a minute. I had to shut it down via the Task Manager.

Then it got worse, and now it won't start at all. After I click on the icon to open iTunes (I have Windows 8) the screen turns white, the blue wheel spins and nothing happens. When I hold the cursor over the iTunes icon in the task bar I can see two preview tiles (one for Download and one for iTunes itself), but both are blank (all white) and nothing happens - the blue wheel will spin forever. What do I do?

I do have the latest version of iTunes. If I uninstall and reinstall iTunes, will that solve the problem? And will the content of my library still be there? Thanks!