Restrict user create, update and delete records

Hi all. I had created roles, administrators and users. I want only administrators can create, update and delete records from database. I had created access rules for user. I deny user access the App_Data and _UpgradeReport_Files folder. When i use User account to login the website, i still can create, update and delete records. For your information, i'm using Visual Studio 2005 and Acces 2000 database. Can anyone tell me how to use the Web Site Administration Tools to restrict user access? Thanks!
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