I would uninstall that one myself. That's a relatively old version of Apache, and you'll need a newer one to support 5.4 PHP versions.
Go here: http://www.apachelounge.com/download/
Download one of the newer versions (2.2.23 or 2.4.3 preferably). Also download the VC9 compiled handler for your php version under the modules. That one is under php5apache2_4.dll-php-5.4-win32.zip for example for 5.4.
Then go here: http://windows.php.net/download/#php-5.4
and download a version of 5.4 PHP. Use a .zip install for win32 VC9 thread safe. Extract that wherever, drop the php5apache2_4.dll into that directory, and extract the apache download wherever. Configure the httpd.conf and php.ini, then use the command line to install the httpd.exe -k install options.
Or you can use wamp as well. I hear its easy to install, and its just a bundled version of apache, mysql and PHP. That would save you having to get a mysql install as well. Personally I find all three of these easy to install, but I've also been doing it for over a decade.