I have purchased a movie through the iTunes store, but I cannot get it to load to my iPhone. If I try to watch it on my PC, the video hangs up every few seconds, but the audio continues to play.
You could try syncing it to the iPhone, instead of redownloading it to the iPhone. For more info about syncing to the iPhone using iTunes, take a look at this doc -> iOS: Syncing with iTunes
For the video not playing in iTunes, one of these should help.
iTunes for Windows XP: Troubleshooting video playback
Troubleshooting iTunes for Windows Vista or Windows 7 video playback performance issues
To add clarity, can you tell us how you are trying to view on your iPhone, are you syncing from iTunes or are you downloading as a past purchase directly to your phone?
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