HDD died, how do I recreate the secondary?

I have a few servers that are part of the RDS. The HDD on one of my secondaries died so when I replaced the HDD that server is no longer part of the RDS. When I try to add a secondary I get an error that IP already exists. How do I delete that secondary if it is not showing up in the RDS or how to I associate the new HDD?

This is a test enviroment which is why I did not have the drive mirrored, but as this could be a real problem I would like to know how to fix it.