bootmagic makes all these problems go away.
0. make sure you have or leave space for a windows partition, a linux partiton and a fat/fat32 partition.
1. to get windows back (skip if windows loads by default or linux not installed yet) follow the instructions to load the windows recovery console and then fixboot and fixmbr, or if not yet installed then install it
2. install linux (skip if already done) taking care to set advanced grub options and not to install grub/lilo on the mbr. removing the non linux partitions from grub/lilo's list is helpful but not required
(you can do 1 and 2 in either order)
3. repeat the instructions in step 1 to get back to windows if necessary
4. install bootmagic if not already installed, making sure you check the enable bootmagic box and add both the windows and linux partition (the one you installed grub/lilo to, not the swap space or any other partition) to the list (they should already be there).
e-mail me if you have trouble.. bXurgess@emaXil.com (remove the two X's)