Cannot drop database because it is currently in use

 Try find the lock or SPId using the database  using the following command

SP_WHO 

Then run

 kill <SPID>;

example kill 60; to kill the process.

Or the folling script also generate the kill script for the database 

DECLARE @DatabaseName nvarchar(50)

SET @DatabaseName = N'Your database name'

DECLARE @SQL varchar(max)

SELECT @SQL = COALESCE(@SQL,'') + 'Kill ' + Convert(varchar, SPId) + ';'

FROM MASTER..SysProcesses

WHERE DBId = DB_ID(@DatabaseName) AND SPId <> @@SPId

SELECT @SQL ;