I used www.google.com/linux
, search phrase "change partition type" in quotes, and found this:
That gave me an idea: boot from a live cd. It will show you all the partitions it finds. Mount and inspect them one at a time until you find the one with /etc directory. Read the fstab file to see the partition information for the system, the mount points, and the filesystem type.
If the information in the link I gave you is correct, it may be possible to change the partition type without loosing data.