I know this problem ( not very well
), a friend of mine had the same problem with grub which kept printing ( GRUB GRUB .... ).
I think your hard disk is clean, the problem is with your MBR ( something messed it up ).
You should backup your data first and re-install LILO ( I'm not sure that will fix it ).
What I did with my friend is to re-partition which has fixed it ( his hard disk is 7 years old now
I hope that will help.