cannot click on anything in iTunes?

My guess is that you have not gotten rid of a modal dialogue box, and this is why you cannot click on anything on the main screen.

A modal dialogue requires a response from you before it disappears and you can access a main screen or the rest of an application.

You seem to not quite understand the technology. iTunes is not charging your iPhone, your Mac is -- when you plug the device into the computer it starts charging. Also, having a new or different computer has nothing to do with your having material on iTunes. If you have purchased material from iTune, all such material should be associated with your account, and you should be able to download it again, onto your new computer, once you have set up iTune properly. Also, iTune is now using the Cloud, which allows you to sync all your devices to your iTunes account, which means that any material you purchase on iTunes should be accessible on any of your devices, and, in the case of a smartphone for example, you can play a tune from the Cloud -- stream it rather than having to download it.

the first screen you come to after agreeing to the terms & conditions is asking you a question, you have to click an answer before you can click on anything else - at least thats how it was for me last night after installing latest version...