Hi DaveS1963,
First of all, congratulations on the purchase of your new MacBook Air. I understand your daughter downloaded a movie from the iTunes Store but it will not play. Was this a movie rental or a purchased movie? Is it possible that the movie did not completely download? Here are a couple of resources that will explain the process.
About renting movies from the iTunes Store - Apple Support
https://support.apple.com/en-us/HT201611
Download past purchases - Apple Support
https://support.apple.com/en-us/HT201272
iTunes Store
- Open iTunes and go to the iTunes Store.
- Click Purchased in the Quick Links section.
- Select the content type that you want to download (Music, Movies, TV Shows, Apps, or Books).
- Select Not in My Library to view purchased content that isn't on your computer.
- Find the item that you want to download. You can browse using the menu to the left. If you have more than 2,000 songs, you'll see Recent Purchases instead of All Songs or Albums.
- Click the Download icon next to the item you want to download.
If an item is already in your library, the Download icon won't appear.
You might find the answer to your question below:
If your download was interrupted, learn how to resume the download.
I hope this information helps ....
- Judy