There are no free password crackers available, but you could pick one up for a few dollars, especially one that looks at Excel, Word, Powerpoint and in some cases, other applications too.
You can demo versions, but they typically on look at the first 1, 2 or 3 characters of your password.
If you are in desperate need to get into a document, let me know, or send me the document with an idea of the length of the password and I'll see what I can do:
hasitbakhda@yahoo.co.uk