I assume you want the user to reach your home page from a bookmark and only your home page.
This can be done by assigning a session-level variable to the user and if they attempt to open a page without that variable being in their session-cache, send them back to your home page.
Need to re-register ASP.NET?
C:\WINNT\Microsoft.NET\Framework\v#VERSIONNUMBER#\aspnet_regiis -i
(Edit #VERSIONNUMBER# as needed - do a DIR if you don't know)