Hey there Superluigi6,
It sounds like you are unable to watch an HD download becuase of the message saying that your display must support HDCP. Here is some more information on why you are getting that message:
iTunes for Windows: Unable to view or play HD video content that requires HDCP
http://support.apple.com/kb/ts3354
"To play this movie in HD, you must have a PC with a built-in display or have it connected to a display that supports HDCP."
High-bandwidth Digital Content Protection (HDCP) is a security feature requiring the use of HDCP certified products in order to display digital media like High-defintion (HD) video. In iTunes for Windows, in order to view HD content, both the display hardware (computer screen, LCD, external monitor, and so on) and video card driver must support HDCP. For additional information on purchasing and viewing HD Videos, refer to iTunes: Purchasing and viewing HD Videos.
If you need to download the non HD version you can do so from Purchases in iTunes:
- Click iTunes Store near the top of the iTunes window.
- Click the Purchased link at the right of the iTunes Store homepage (below Quick Links).
- In the page that appears, select a category.iTunes shows you which of your purchases are available for download. You can view all of your past purchases, or just the ones not currently in your iTunes library. Items already in your library aren’t available for download.If you select Music, you can view your purchases by song, artist, or album. If you’re viewing by album, click an album to see which songs on it are available for downloading.To search for an item, type its name or a keyword in the search field, and then press the Return key to view your search results.
- To download an item, click its Download button .
From: iTunes 11 for Windows: Download previous purchases from the iTunes Store
http://support.apple.com/kb/PH12491
Be sure to uncheck the Download HD When Available in the lower right corner before downloading the movie.
Thank you for using Apple Support Communities.
Cheers,
Sterling