In SQL Server, you can use the system function "sp_who2" to check for currently running or blocked queries. This function returns information about all active connections and sessions on the SQL Server instance. You can filter the results to show only blocked queries by adding a WHERE clause to the query, such as "WHERE BlkBy <> 0" which will return all rows where the BlkBy column is not equal to 0, indicating that the query is currently blocked.

Another alternative is to use the Dynamic Management View (DMV) sys.dm_exec_requests which contains information about all requests that are currently executing within SQL Server. You can filter the results to show only blocked queries by adding a WHERE clause to the query, such as "WHERE blocking_session_id <> 0" which will return all rows where the blocking_session_id column is not equal to 0, indicating that the query is currently blocked.

You can also use SQL Server Profiler to trace the events of your database, to trace all the running queries and also to trace the blocked queries.