Lilo configuration

We have a Pentium Pro machine with NT 4.0 and Slackware Linux 2.0 on the same removable system drive.  It used to come up to the LILO prompt for either "dos" or "linux".  Now, as the machine boots, it only comes up to "LI" instead of "LILO:".  When I take this disk out and replace it with one with only NT4.0 on it, the computer still boots to the "LI" position.  Is there an easy way to tell what is going on, or do I have to reinstall linux.

Thanks in advance.