I can tell you why it happened. the LI boot prompt happens when the second stage bootloader loads, but it cannot run. Did you NOT rerun /sbin/lilo after you changed a kernel (If you DID change a kernel). Did you use /sbin/lilo incorrectly if you created a new boot map? Then again, you could have a corrupted MBR. Or you may have installed LILO in a swap partition (which should be impossible). You might be missing a kernel image in /ect/lilo.conf. Either way, you must do what trickykid said and reconfigure lilo.