Corrupt pdf file

I am trying to open up a pdf file that I had saved last week. It is about 17 MB. I emailed it over to someone, who couldn't open it. I am now trying to open it on my laptop where I had saved it, and it doesn't open up via Reader. After a very long time, it says 'can't open file - there is a problem with the file format,.

When I had saved it last week, i had then managed to open it fine. It just doesn't open now. Is there anyway I can either recover parts of it at least, or would there have been an 'autosaved copy' anywhere from last week.

Thank you in advance for your help