It depends on who has logged in and what role that particular logged user is defined in the system.
On high level, user logs in and based on the successful authentication, you are aware of the user. This user has predefined role (set at the time of creation of the account). Based on this role, you know if he is an admin or a normal user. According to the role, you take action and display.
Either, define roles by yourself and attach them to users at the time of account creation OR
use ASP.NET roles feature.
Understanding ASP.NET Roles and Membership - A Beginner's Tutorial
Authenticate User by Roles in ASP.NET
MSDN: How To: Use Role Manager in ASP.NET 2.0