A GIMP file got corrupted. Can it be fixed?

Um. I guess this is the right place to write this...

I've been working on an art project all week. It's not for school or anything, but it was a birthday gift for a friend who's a bit upset and stressed at the moment, so it would mean a lot to me if I could rescue it somehow.

Yesterday I went over to my friend's house. My laptop overheated right before I left (it's kinda old and the fan doesn't always work) and I just flicked the wall switch off and left it because I was going out, but when I got back today and turned it on I tried to open the image up and got a pop-up saying 'Opening 'C:\Documents and Settings\User\My Documents\My Pictures\Fun in the Sun Colour.xcf' failed:

GIMP XCF image plug-In could not open image'

I've had a pop-up like this once before after a similar event, but that one said that the image was corrupted and that even partial image data could not be recovered. I didn't worry about it that time because it was just a picture I'd been using to practise my digital colouring on and I just figured it had something to do with the overheat, but my laptop has since overheated many times while I was using GIMP without there being a problem. I don't understand why it only happens occasionally and not all the time.

Does anyone know any way that I can fix this file?

It's completely typical that this would happen the one time that I didn't make a .jpeg backup. >_<