Purchased TV Show will not play - Screen stays black and progress bar won't move
It could be many things from a missing video codec, to a corrupted iTunes/Quicktime installation, to an old video driver or hardware acceleration on the video driver.
Find a video that doesn't play that you have purchased already. Don't use rentals or streams.  This gives you a baseline to test without incurring additional costs.
Make one change at a time then test iTunes with the known troublesome video.

Make sure Windows is up to date run Check for Updates.
Go to your computer manufacturers support web page look up your model and check the video driver version verses the one you see in Device Manager. Upgrade it if it is not the latest version. Some vendors provide tools to make this easier. These tools help you keep your drivers up to date, run such a tool as an alternative option.
Turn off Hardware Acceleration (Display Settings -&gt; Advanced Settings -&gt; Troubleshoot -&gt; Reduce Hardware Acceleration)
Run Disk Cleanup to clear your Temporary folders.
Run virus/malware scans.
Run a Disk Check (Right-click drive -&gt; Properties -&gt; Tools -&gt; Check)
Delete &amp; Re-download the purchased content
Follow this Apple Support guide to completely uninstall, re-install iTunes on Windows. https://support.apple.com/en-us/HT204275 Also uninstall Quicktime if you have that installed.

It's possible that Apple had technical difficulties, some people report a video that had a black screen working properly at a later date with no changes made on their part.
You can actually report the problem and possibly request a refund from Apple for those rentals that didn't work. https://support.apple.com/en-us/HT204084