to which php.exe do I assing the .php files to open??

[ranger]

Hello!
Today I installed xampp succesfully.
Only problem was that I has to assign a program to open .php files.
I opted for php.exe, but now I wonder maybe I should have assigned php-win.exe to the .php files.
So I tried to change this on my XP pc by clicking on a php file and then select open with php-win.exe but that this change didn't happen no matter how many times I tried it.
Could someone tell me which php.exe or php-win.exe should be the standard opener for .php files. And if XP refuses to perform a change what I can do to fix that too...
Thank you.
ranger