Drop a SQL Server database
Let's say you have a database named wildlife, kick the users off and detach the database.

This can be done via the SSMS GUI, right click, under all tasks.

-- Kick off users, roll back current work
ALTER DATABASE [WILDLIFE] SET SINGLE_USER WITH ROLLBACK IMMEDIATE;
GO

-- Detach database
sp_detach_db 'WILDLIFE'
GO

However, the *.mdf and *.ldf files are still there.  Shift delete them so that they do not go to the recycle bin.

Good luck!

PS:  Check out my blog for more information.
http://craftydba.com/?p=1753