After you configure your authentication provider for AspNetSqlMembershipProvider and modified your Central Admin web.config also, when you try to access the Central Admin, it will ask for the password and will not let you in. If you come across this problem, just make sure you modify the provider as follows:
<roleManager enabled="true" defaultProvider="AspNetWindowsTokenRoleProvider"> <providers> <add name="MyAspNetSqlRoleProvider" connectionStringName="MOSSSqlServer" applicationName="abcd" type="System.Web.Security.SqlRoleProvider, System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" /> </providers> </roleManager>