I did the "fdisk /mbr" command two weeks ago and not only LiLo was gone but also the bootfiles for XP

Be sure you have made XP restore/emergency disks before proceeding.
This is only a problem when you were triplebooting before. Meaning after lilo is removed you still want to double boot.
Owh many people seem to use bootpart.exe
However I havn't got any experience with it.