mysqli is not showing in phpinfo, i have added the respective line in php.ini already (in php version 5.2.0)

mysqli is not showing in phpinfo, i have added the respective line in
php.ini already (in php version 5.2.0)

My configuration is
windows xp
running php 5.2.0 in
apache....,
i have enabled mysqli extension in php.ini file...., my line is as follows
extension=php_mysql.dll
but it is not showing in phpinfo()
that is why when i use
mysqli_connect()
it throws the following error
Fatal error: Call to undefined function mysqli_connect() in C:\Program
Files\Apache Software
Foundation\Apache2.2\htdocs\email\phpmaster\test\view_mail.php on line 2
to be noted that i have restarted the apache as well as windows xp, but
unable to load this extension, however other extension works
Thanx in advance:---