Grub error 17 : Cannot mount selected partition
This error is returned if the partition requested exists, but the
filesystem type cannot be recognized by GRUB.
So, it seems your /boot/grub/menu.lst points to a partition which grub doesn't recognize. Is it the only partition on the machine, other than swap?
How long ago did you install Suse?
It would help if you could copy menu.lst (you will need root priviledge to access it) and /etc/fstab and post them here.
Try booting from the install cd.