We often run into this in our QA environments. The below script is a blunt hammer approach to remove replication, no matter how fubared your server is:

USE <yourreplicateddb>

EXEC sp_removedbreplication '<yourreplicateddb>';

go

USE master

EXEC sp_dropdistpublisher @@servername, 1, 1;

EXEC sp_dropdistributiondb 'distribution';

EXEC sp_dropdistributor;

Note that the third parameter for sp_dropdistpubisher is an undocumented parm, but if you look at the code, it allows things to be forced.