type "ls" to view partitions. Mine listed things like: (hd0) (hd0,msdos6) (hd0,msdos5), etc
then type, say: "ls (hd0,msdos5)/" across all your partitions until you find a directory listing that contains your linux /boot directory
Once you find the partition, set the prefix like so: "set prefix=(hd0,msdos5)/boot/grub"
then enter: "set root=(hd0,msdos5)"
do "insmod normal"
do "insmod linux"
do a "ls /boot" to find out the name of the latest "vmlinuz-2.6.38-14" and the "initrd.img-2.6.38-14-generic" or whatever it ends up being
in my case, I did a "linux /boot/vmlinuz-2.6.38-14-generic root=/dev/sda5 ro", which was the latest vmlinuz version number in my directory listing
set the initrd with the same version as above. In my case, it is "initrd /boot/initrd-plymouth.img"
Your system should hopefully boot into linux at this point. You booted into linux, but these changes are not permanent. To make them permanent, go into the command prompt and enter the following command: "sudo grub-install /dev/sda"
I've just changed one line, which is highlighted in yellow.