SQL server is slow, database update wont run?

Some useful SQL queries to get who is connected to a database, long running queries, queries that lock the database, high cpu queries.

Who is connected?

Sp_who
or
Sp_who2

Kill session:
Kill [SESSIONID]

Long running queries:
SELECT sqltext.TEXT,
req.session_id,
req.status,
req.command,
req.cpu_time,
req.total_elapsed_time
FROM sys.dm_exec_requests req
CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS sqltext

High CPU:
SELECT s.session_id,
r.status,
r.blocking_session_id 'Blk by',
r.wait_type,
wait_resource,
r.wait_time / (1000 * 60) 'Wait M',
r.cpu_time,
r.logical_reads,
r.reads,
r.writes,
r.total_elapsed_time / (1000 * 60) 'Elaps M',
Substring(st.TEXT,(r.statement_start_offset / 2) + 1,
((CASE r.statement_end_offset
WHEN -1
THEN Datalength(st.TEXT)
ELSE r.statement_end_offset
END - r.statement_start_offset) / 2) + 1) AS statement_text,
Coalesce(Quotename(Db_name(st.dbid)) + N'.' + Quotename(Object_schema_name(st.objectid, st.dbid)) + N'.' +
Quotename(Object_name(st.objectid, st.dbid)), '') AS command_text,
r.command,
s.login_name,
s.host_name,
s.program_name,
s.last_request_end_time,
s.login_time,
r.open_transaction_count
FROM sys.dm_exec_sessions AS s
JOIN sys.dm_exec_requests AS r
ON r.session_id = s.session_id
CROSS APPLY sys.Dm_exec_sql_text(r.sql_handle) AS st
WHERE r.session_id != @@SPID
ORDER BY r.cpu_time desc

Transcation Locks:

SELECT  L.request_session_id AS SPID,

        DB_NAME(L.resource_database_id) AS DatabaseName,

        O.Name AS LockedObjectName, 

        P.object_id AS LockedObjectId, 

        L.resource_type AS LockedResource, 

        L.request_mode AS LockType,

        ST.text AS SqlStatementText,        

        ES.login_name AS LoginName,

        ES.host_name AS HostName,

        TST.is_user_transaction as IsUserTransaction,

        AT.name as TransactionName,

        CN.auth_scheme as AuthenticationMethod

FROM    sys.dm_tran_locks L

        JOIN sys.partitions P ON P.hobt_id = L.resource_associated_entity_id

        JOIN sys.objects O ON O.object_id = P.object_id

        JOIN sys.dm_exec_sessions ES ON ES.session_id = L.request_session_id

        JOIN sys.dm_tran_session_transactions TST ON ES.session_id = TST.session_id

        JOIN sys.dm_tran_active_transactions AT ON TST.transaction_id = AT.transaction_id

        JOIN sys.dm_exec_connections CN ON CN.session_id = ES.session_id

        CROSS APPLY sys.dm_exec_sql_text(CN.most_recent_sql_handle) AS ST

WHERE   resource_database_id = db_id()

ORDER BY L.request_session_id