I have two word files (see attachments)
New Notes One Dimentional Motion.doc
New Notes One Dimentional Motion.docx

When the user opens the DOCX in word and tries to scroll down the machine freezes up (eventually it catches up but you probably know this isn't the best scenario to happen during class). However, when the file is saved as a DOC, word has a much easier time scrolling through the document.

The simple answer I gave to the user was to use DOC files which he is doing, but it would be helpful to know if there is something wrong with the way he is creating the files so I can let him know a better way to use these documents in his lessons.