[Nottingham] Non booting USB key

[stripes]

Can anybody advise please on this?

I have a bootable usb key running Ubuntu meerkat but for some reason
it won't boot on the system I currently have access to (hangs part way
though boot). It has some files on it that I need  so have booted
debian and mounted with the following command

sudo mount -o loop /media/CORSAIR/casper/filesystem.squashfs -t squashfs /mnt

ls /mnt shows the directories and many files but not the ones that
have been saved on the stick only seem to be the system files. So
where does Ubuntu put files that you save on a bootable usb

Stripes