I’ve worked as an editor before. Probably one of my used tools in Microsoft Word was the track changes feature. But sometimes, when some subeditors work on a document, they forget to enable this feature so the changes become lost in space. That can be a big hassle and a crimp on the workflow.

Codejacked wrote about three ways to compare two versions of a Word Document. And here they are:
• Use another Microsoft Word feature. Merge the two documents to create a third and Word will automatically track changes. A caveat here is that Word can sometimes mistake an older document with a newer one - so additions may come up as deletions in some cases.
• Use an external compare tool like WinMerge (but it only works with ASCII file so you still have to convert you Word documents. Needless to say, formatting will be lost). I personally use PSPad for these types of jobs but I use it mostly for codes, not for documents.
• Use another app called CygWin. But you better read on more on the details for this one.

Read more on the details here.

Source: Codejacked