At work we needed to get into change a password protected word document of which everyone had forgotten the password. To do this my colleague found a great tip for removing passwords.
Here it is
1) With the document open press F11 while holding down shift and alt (Alt-Shift-F11). This should launch the script editor in Word.
2) Next select the find option (or hit ctl-f), and run a find for the word "password." This should highlight something like this "32943208".
3) Delete the letters and numbers between the tags (in the above example this would be the 32943208).
4) Save the document in the script editor and close the window. You should now be back in your Word document.
5) From the "Tools" pull down menu, select "unprotect." Your document should now be unprotected.
This should work the same way for Microsoft Excel.
Great tip thanks to Ashley Kozaczek.