noob question help - Fatal error: Call to undefined function..

I know this is probably the noobiest of questions but please help. Fatal error: Call to undefined function mysql_connect() in c:\TSW\forums\ips_kernel\class_db_mysql.php on line 112 This occurs when I try to access a MySQL application, specifically Invision Power Boards. I have PHP5 installed on my Apache 1.3.31, and I believe that my MySQL is MySQL4, all this on Windows XP personal. My php.ini file is in my systemroot (C:/windows). Currently I have no loaded extensions for MySQL/php connections stuff (ex: php_mysql.dll, php_mysqli.dll). I tried some stuff I found on help boards but everything just got all messed up, so I thought I'd get more official help. I have all of the php .DLL files that came with the zip file in C:/windows/system32. PHP-mysql.DLL and php_mysqli.dll are in both system32 and just c:/windows. When I run phpinfo() I get no mention of MySQL. MySQL itself connects to the MySQL server just fine. I think that's everything. Thanks in advance.