How to connect excel(If I consider it as a database) with a websit
 

Suppose I have created a dynamic webpage using asp.net now I want to connect
it with excel.Say my web page contain a provision where user need to create
an account for the 1st time using by giving a username,password and also
some details(like first name ,last name etc.) so that he can access a
specific account.The username,password and details of that user I want to
store in excel automatically.So I need to connect it with excel .Then, when
that particular user will log in for the 2nd time it ll automatically check
from that excel database that wheather that user is an exsisting one or
not.If the user is an exsisting one then he ll again able to accses his
account and If not then he have to registerfor a new account.So I want to
know how I can connect it with excel.