--Use sp_who to determine which session(s) are in "suspended" mode (waiting for I/O or taking for-fucking-ever)
use AdventureWorks2014;
go
exec sp_who;
go

--Query the session in question and see what the cocksucker has executed
DECLARE @sqltext VARBINARY(128)
SELECT @sqltext = sql_handle
FROM sys.sysprocesses
WHERE spid = (56) --56 was the session in question
SELECT TEXT
FROM sys.dm_exec_sql_text(@sqltext)
GO

--Kill the session causing the problem
kill 56;
go