webpage's error

My error is:
Warning: mssql_pconnect() [function.mssql-pconnect]: Unable to connect to server: etc.

my web is ultimate web eternal and my connect code:

Code:

---

<?php
function Conectarse()
{
global $link;
if (!($link=mssql_pconnect("ROBERTO-095B4BC\SQLEXPRESS","sa","simeimporta")))
{
exit();
}
if (!mssql_select_db("UserLogin",$link))
{
exit();
}
return $link;
}
Conectarse();

---

i'm use windows autentication
help me please

Check your password. Your password is "simeimporta"?
Try to change the password.