Copy and Paste loses formatting!
One of my clients had a problem this morning, copying and pasting from one Word document to another. Once on the clipboard all the formatting had disappeared. So pasting the contents to a new document looked totally different.
Some investigation found that this was related to having Google Chrome open at the same time. Closing Chrome, and reopening Word resolved the problem short term.
In fact the culprit was the Skype Click to Call add-in. Uninstalling this from Programs and Features resolved the issue completely.
Hope this helps someone!