Just dispensed some advice to a client in trouble. It's a little trick that's helped me out a few times before so I thought I'd post it here in the hope others may find it useful.

If your Excel or Word document corrupts while your using it and you have trouble opening the document then a good first-step to rescuing the document is to download the free office application Open Office open it in that and remove the corrupted area. Open office seems a lot better at handling corrupted files than Microsoft Office (I also suspect it's a lot better at not corrupting them in the first place). This isn't a plug for Open Office, just a trick that's worked for me on several desperate occasions.

A friend has also carried out a similar trick by transferring a corrupt Excel file to a Mac and opening it in Numbers - Apple's equivalent to Excel. Again no plug for Apple here just something that works.