please post code on board, never in a word document, word may chose to reformat the quotes breaking it. I really hope you don't write your code in word.
the problem
$get = mysql_query("SELECT count(id) FROM login WHERE User_Name="$username" and Password="$Password"");
if your encapsulating your sting in double quotes, you want to use single quotes around the vars for the query.
Also watch the case, password and Password are not the same