You can run both from the same Apache install by setting up virtual hosts.
On windows you can edit your hosts file and add the line
127.0.0.1 localhost2
That drives your browser to localhost when you type localhost2, and apache will then deal with the request. Shove something like this in your apache conf
NameVirtualHost *
<VirtualHost *>
ServerName localhost
DocumentRoot e:/myphp/
</VirtualHost>
<VirtualHost *>
ServerName php
DocumentRoot e:/myphp/php
</VirtualHost>
You might also have to add some directory permissions - just type localhost/manual into your browser and Apache should open up some learning