A) Open document > Select edit menu > choose select all > then choose copy from edit menu.
Open new document > edit menu> paste.
Select tools menu> choose options> window opens with options. Select form different tabs the edit tab> make sure that al desired boxes are selected.
Select save tab>choose and mark box>ask about properties
accept or Apply options and close.
Save new document different name. When saving it should ask if you want to save properties> choose not save. Maybe it asks if you want to modify properties> choose yes> select box archive amongst read only, hidden or archive.
If this does not work.
B)There are many 3rd party utilities which claim to reset forgotten word password:
The program that I recommend is the Excel Password Recovery 5.0 It recovers/removes the "Password to Open" and "Password to Edit" for you to view and edit the document freely.
http://www.recoverlostpassword.com/products/excelpasswordrecovery.html