If you need to run PHP scripts (from the command line) from a directory other than
C:/PHP you need to add the path containing
php.exe (which is probably
C:/PHP) to your
PATH environment variable. You can then use
php yourscript.php on the command line anywhere you like - just be wary that relative paths for
require()'s and such won't work unless you're in the right place.
To have your scripts be served by your web server from different directories, you will need to configure your web server by creating a virtual directory. You'll need to refer to the documentation of your web server here, since you don't mention what it is.