So If you did as everyone else said and found the folder "Office 2008/09/11 AutoRecovery" and your file is still NOT there, that means it is being stored in your computers Temporary or "-Tmp-" folder.

The "-Tmp-" folder is very hard to find, even if you have made hidden folders visible, so what you need to do is go to "Applications"- "Utilities"- "Terminal"

Once you are in the terminal copy this phrase: "open $TMPDIR" and press ENTER. That will open your Temporary files folder where you will see another folder named "Temporaryitems"

Open up the "Temporaryitems" folder and you will find your lost file, that even AutoRecovery could not find. However when you do find your file, make sure you open up the document with "TextEdit" because a .tmp file will not work with Word.

An example name of your lost document will be "WordWorkfile D-57238.tmp"