Can you elaborate on "windows won't start"?
If it's an actual Windows error, then your data hasn't been deleted. You can just re-install windows and all your photos will be fine. Or you can stick the HDD in an external-casing and get to them that way.
If it says "Hard drive failure" or something like that when you boot up though, then that could be a little more problematic.
One of the other tech geeks here will be able to help further. good luck