Q: Why can't I open iTunes 11?

I have been having major issues with my iTunes since about March now; I saw that iTunes had a new update, so I downloaded it. However, something happened and my iTunes (including my ENTIRE library) was deleted.

I have been trying, with very little success, to reinstall iTunes 11 onto my Dell.

I get the message that says the software was downloaded, but I can't open the file for some reason. I have deleted and redownloaded so many times, and I'm honestly at the point where I want to just say "eff", buy a Zune, and move on with my life.

What's a girl to do?! Please help!

Thanks,

Sarah