To find out what queries are currently running on your SQL Server try the following query.
FROM sys.dm_exec_requests req
CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS sqltext
Keep in mind that the results of this query will include this query itself, so the result will always be at least one row returned.
If you decide you want to kill one of the queries you can use the kill sql statement and the session id (see the second column).
The system is simple:
KILL <session id here>
I owe the basis for this post to the following post: http://blog.sqlauthority.com/2009/01/07/sql-server-find-currently-running-query-t-sql/