Windows 7: How do i edit video description?

I literally feel like I'm losing my mind. I've tried to figure out how to do this for the past hour and it CANNOT BE THIS DIFFICULT.

When I open a file in Windows Media Player, or DivX there is a column for "description". When I try and click in the blank space, it won't let me edit it. When I right click on the file and click properties (in windows media player), I see the area where a description can be entered and it's just blank. I can't edit it. When I right click on the actual .mp4 file on my desktop and go to details, there is 5 items under "description". Title, Subtitle, Rating, Tags, and Comments. No matter what i enter in each area, nothing will show any information in the "description" column of DivX or Windows Media Player.

Someone help me. How do I add a description to a .mp4 video file?!?!

Check out this site! I think you should be able to find what you need here!

Windows Media Player: Add or Edit Media Information

I hope this helps!

Brett M,
Windows Outreach Team