Q: how do i log into my itunes account from my windows computer?

Open iTunes.  To authorize, go to the Store menu item on the menu bar, and choose Authorize This Computer, as shown below.  Then you can log in to your account with your Apple ID and password.

If by any chance you don't see the menu bar ("File, Edit, View, Controls, Store, Help"), first enable it by using CTRL+B.

Thanks so much!!

im on a chrome notebook how can i log in itunes

Chrome OS is not a supported platform for iTunes.

tt2