http://users.bigpond.net.au/hermanzone/p15.htm#17
Basically, the menu.lst is probably not correct. You can mount your linux install with any linux live CD, then chroot into the install and modify the menu.lst file.
Also see the Grub Booting Tips in my signature. Task H2 helps you mount the partition and chroot into it. Then just edit the /boot/grub/menu.lst.