To save your not-so-important (see my signature) data
Boot from live CD and have a usb-stck/external HD ready; after the boot insert it.
Mount your Ubuntu partition; if you had a separate partition for the home directories, mount that one (see earlier post; sudo mount /dev/sda5 /mnt).
Copy your files from /mnt to the usb-stick / external HD
Unmount the usb-stick / external HD (see earlier post; sudo umount /mnt)
Why am I so cynical about the not-so-important data?
What would you have done if you had a serious physical disk crash? You might have been able to get it back partitally by using a professional service that charges you a hell of a lot of money for each MB that they recover.
Making backups would prevent this.
If a document that I'm working on is important for me, I always save it twice. Once on HD and once externally (e.g. usb-stick)
Good luck in getting your system back up and running. Above post by garvinrick4 seems quite reliable