Thanks for your reply,
i'm only adjusting in size some of the partitions on the disk, i'm not adding or deleting any partition. But i've read somewhere that lilo stores in the MBR a direct link to the lilo loader; if this loader is moved, than lilo fails to start.
I have to resize the partition using windows, therefore if i'm not able to start linux i can't run lilo and fix it.
Has anyone ever done this before ?