You could try if OpenOffice Writer (
http://www.openoffice.org/) could open
it. Sometimes that product is better at opening corrupted or too large
documents than Word is.
If that doesn't work, is your document a docx file (Word 2007 version)? If
so, you could change the extension from docx to zip and go into the archive.
Maybe you can remove some graphics or stuff in the hope the document will
become smaller and then try to open it. It should have some linking errors
for the missing images, but you should be able to open it.
Yves