I have seen these issues before when you use the Microsoft SQL Server Migration Assistant 2008 for Access.
When you use this tool to upsize the database from Access to SQL Server it places in allot of extra constraints in the database which are not required.
To fix the issue follow the steps below:-
1. Open the database in SQL Server Management Studio 2008
2. Right click on each database table and select 'Design' from the menu
3. On the right hand side you will see the table design shown, Right click on anywhere there is white space in the same pane and select 'Check Constrains...'
4. In the Check Constraints window if there are any constraints listed for the table delete them
5. Once the Constraints are removed close the Constraints Window and Save the table
That should be it the database should be running fine after that, however you should also download the Database Optimsation Tool from the link below so that the important indexes are rebuilt:-
http://www.webwiz.net/webwizforums/webwizforums_downloads.asp