won't boot from HD, only floppy L 99 99 99 ...

I had to re-install Knoppix 3.3 to the HD of a laptop last night, but when I try to boot the computer I get the "L 99 99 99 ....." error at the beginning of the boot process & LILO never starts. I did make a boot floppy during the install and when I use the floppy to boot the computer, it will read the LILO boot info from the floppy then continue to boot successfully from the HD.
How do I repair/reinstall LILO on the HD so I won't have to use the floppy? Thanks in advance.