I am using SQL 2008 64 bit version and we are seeina performance problem. In the analysis we found that there are more Adhoc queries has been build up. Not sure how to avoid these queries.
How is the performance issue manifesting itself? With SQL Server 2008 ad hoc query plans also get cached, so are you seeing plans being more recompiles because the number of queries?
If you want to limit ad hoc queries you would need to write stored procedures and then limit direct able access.