SQL Server : Data Login Failed error

Question

Dear members,
I am facing one error while operating software (own made) into laptop (operting system Windows 7 Ultimate) This software has been made on OS -Windows XP and Sql Server 2005 which machines name ADMIN/Administrator. I am trying to change same name to laptop ADMIN/Administrator but laptop's name ADMIN/PC could not be changed hence it shown as ADMIN/PC, SQL JIT debugging error 'Loging failed for user ADMIN\PC' while generating reports and datagrids. How to resolve this problem?             
Thanks!

Vilas Gite