I got this from another forum:
First you need to figure out on what partition/drive your Windows install is. If you don't know this already, a realtively easy way to find out is to run, in a terminal, as root fdisk -l. That should print a lot of stuff, you're interested in the line that says "W95", "NTFS", anything relating to Windows, or something that has * on the second column, line thats hould look something like this:
/dev/hda2 * 7 898 7164990 7 HPFS/NTFSThe magic string you're looking for is of the form: (hdX,Y)
X is the number of the drive, counted from 0. So, if you only have one drive, or the one you have Windows installed on is the first, X is 0. If it's the second, it's 1 and so on.
Y is the number of the partition, taken from above (/dev/hda2), minus 1.
So, in our case, the magic string is (hd0,1).
Edit your /boot/grub/menu.lst file, either by typing file:///boot/grub/menu.lst in your favourite browser (either Nautius, or Konqueror), which should, theoretically, spawn an editor. Failing that, in a terminal, run vi /boot/grub/menu.lst. Don't worry, I'll also tell you how to work vi. :-)
If in vi, press i to enter insert mode. Then add the following, under a similar entry:
title Windows install
bootIf in vi, press Escape, to go into command mode, then type :wq and press enter to save and quit. Then reboot and enjoy.