Cannot be played in HD on this computer?

I've purchased Frozen in HD and wanted to watch it on a PC, iTunes said it couldn't play on this computer and demanded another $17 for the SD version. I've adjusted the notebook to 1280x800 and the attached monitor (extended desktop) to 1600x1200, so this is nonsense.

OK, it's a copy protection issue that Apple is being coy and misleading about explaining in the "This cannot be played in HD on this computer" error message. Seems it's a software, not hardware, issue that Apple has created. XP doesn't support the copy protection scheme (HDCP)Apple demands be utilized and I have to have Win7 or 8 or I can't play the content I've paid for.

This is what fixed it for me: Apple OSX system prefs: just set your screen resolution to something that iTunes likes enough to download the HD version. Apparently if iTunes thinks youre on a system that *currently* doesnt meet what it detects as an HD-compatible display, this erroneous error message pops up. I've been 'forced' to purchase an SD movie to play on a large Samsung plasma display, which is 720p. The MacMini running the itunes library for that Apple TV is headless and was set to a screen resolution that itunes didnt care for. Summary - play around with your sys prefs screen resolution. Peace

Thanks this helped me. I probably shouldn't have tried it as a first option but it worked. Here's more information about the CONTROL+SHIFT+OPTION+POWER action.