my computer is not letting me update itunes because "I'm not the administrator" (which I am)

I've been trying to download the latest version of itunes for a couple days now. Everytime I did it, i twould go almost entirely through the download process and right at the end it would say it couldn't finish because i don't have administrator rights.

Last night I decided to see if I could figure out why it was saying that, if some how my settings were changed.

Everything I found, it looked like I was administrator.... this is my first issue

Also, when trying to figure out the admin thing. I ended up deleting my itunes. I tried to restore my computer and bring it back, but only parts of it came back. So I dont know if I need to completely uninstall itunes to be able to reinstall?

But first I have to figure out the admin thing

Thanks