You need to correct these mistakes before you try to use this code
1. This method should return something. Most probably a 'bool' . But it returns 'void'. How are you going to verify the result if it does not return anything ????
public void LogIn(string username, string password)
2. This code should read a value from the reader. But your code ends after this line of code.
SqlDataReader reader = cmd.ExecuteReader();
3. Also this method returns 'void' . Same mistake repeated
public void doLogIn()
4. Even if the user is able to login or not, the session is created for him and redirected to Home.aspx ,irrespective of the authentication result... Then why need the username/password itself ?
Session["uname"] = usernametxt.Text;
5. Passwords are not hashed. Even a student level project does not have plaintext passwords...