Can not run website on IIS? Help me

Question

My application use login control and it run in visual studio good. But when I place website on IIS, run and login then error appear. Error like this: Login failed for user 'TUAN\ASPNET'. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.SqlClient.SqlException: Login failed for user 'TUAN\ASPNET'. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Link source code: http://www.mediafire.com/?sharekey=5052a597ce417c9cd6baebe61b361f7c7ca106c474d223e6a601da0f25e869f4