No I am not, I gave you the link in my first post, if you cant find it then see this :-
http://www.daniweb.com/forums/announcement9-3.html

Edit your post and add to the code tags to it, it should not take more than a few minutes.
And PLEASE write the full words why do you eat up sentences with the "..." and the SMS language(used with Mobile handsets) when you have a complete keyboard in front of you.

where iam doing the mistake?.......................

String mobileno=request.getParameter("mno");
String password=request.getParameter("pwd");

....


Statement s = connection.createStatement();
rs=s.executeQuery (sql);
rs = s.getResultSet();


while (rs.next ())
{
mobileno=rs.getString("mobileno");
password=rs.getString("password");
out.println("MOBILENO=" +mobileno );
out.println("PASSWORD=" +password );
}

if(mobileno.equals(request.getParameter("mno")) && password.equals(request.getParameter("pwd")))
{
out.print("<h1>You are Already Registerd </h1>");
}
else
{
out.println("<h1>You are not a Valid User Please Register</h1>");
out.println("<a href='newregister.jsp'><br>Register Here!!</a>");
}

Ok... Now I am going to just assume how you wish the servlet should work, If you have an already registered user, you want to just display "You are a valid user" and if the user is invalid you want to display "Please register !!".

So lets see where you could be going wrong:-

java Syntax (Toggle Plain Text)

String sql = "select mobileno,password from newuser where mobileno='"+ mobileno + "'and password='"+ password + "' " ;

String sql = "select mobileno,password from newuser where mobileno='"+ mobileno + "'and password='"+ password + "' " ;

Now the above query would return you a database record if and only if you got a valid user with correct mobile number and password hitting your servlet.

So instead of while(rs.next()) you should instead opt for if(rs.next()) like this :-

java Syntax (Toggle Plain Text)

if (rs.next ()) {
  // If we get a record it means the (mobileno & password) 
  // combination is already valid.
  // so just close your statements and do whatever you want
  // for a valid user here.
} else {
  // No records found for user in table, so user is invalid.
  // So put the appropriate message for invalid user and
  // the registration link here
}

if (rs.next ()) { // If we get a record it means the (mobileno & password) // combination is already valid. // so just close your statements and do whatever you want // for a valid user here. } else { // No records found for user in table, so user is invalid. // So put the appropriate message for invalid user and // the registration link here }

And now that I looked at it, Yes the problem IS the 'while'. I was about to say that it made no difference even if it was 'if',
BUT:
When you use While and the query doesn't return anything, the variables: 'mobileno' that are inside the while don't change value, so when later you do:
if(mobileno.equals(request.getParameter("mno")) && password.equals(request.getParameter("pwd"))) It will return true even if there is no entry in the database because you use the old values that 'mobileno'

So use the if statement