using asp.net membership Probvider you can easily
make a user login using username and password and redirect to
default or any page by the following way -

beginners of .net programming can't guess sometime that
how easy is sending mail through .net.there are many ways
to do that.but i am writing here the easiest method to send
mail in c# with .net.It doesn't involve a lot's of coding.
all is built in and no more components.

if you want to prevent running multiple instance
of the same c# application then check the
following lines.It's sometime necessary to prevent
running multiple instances of the same application.

It's required that you configure your joomla SMTP settings so that joomla is able to send
email when user registered or different mailing functions works for other components and modules
like k2, CB....
In this post i show how to configure joomla 2.5/3 smtp settings properly.

command objects use parameters for passing values
to sql statements for type cheking,validation,guarding
against SQL injection attacks,etc.so its a good practice
to use command parameters to sql statements.