to upgrade
read the install guide
http://docs.fedoraproject.org/en-US/...ide/index.html
1) BACKUP important data ( photos,music,excel files,...)
2) see #1
3) see #2
4) download the fedora 18 install dvd
5) burn the iso to dvd
6) reformat the harddrive to ext4 format
7) install fedora 18
8) import your back up music,photos,... into fedora 18