Rescuing files before re-install?

Hi all, just come here after borking up my mums Aspire by trying to install FF3 and applying system updates at the same time. (FF installed fine until updates restarted - now mouse won't move and there's no taskbar. )

Thanks to many other topics here, I'm fairly sure I know what I'm doing to restore everything (Need to get a USB stick first), but am assuming flashing back to the restore dvd will overwrite all the user made documents on the machine(?). Is there anyway to save/rescue these before restoring?

The machine does have a 8gb Expansion card added, I have been wondering what data is saved on that, and if removing that before the re-install would help retain files, or if it would just totally mess up the process.

I am a bit of a computery geek, but I'm a solid linux novice; I can follow instructions fine, but don't really know what I'm doing with a linux terminal or understanding where linux saves it's user files. Any help/advice/links you can give me would be gratefully received.

- Hennell