no php execute on test

[blazerfan]

Ok sorry if the answer is somewhere else I tried searching but too much stuff came up. Here is my deal I am running windows Vista and xampp installed nicely. After several hours of reading I now have 5 test sites running under htdocs under my local host.
However I was attempting to learn PHP:
I did the Hello World everyone learns at first and tried placing the helloworld.php in the root htdocs.
opened Firefox 2.2 and typed in helloworld got 404 error, same if I try localhost/helloworld even decide to try it under one of my working websites failed to work
[list]Same if I run IE7 am completely able to type in either browser loclhast and have the main xampp window comes up as it should and it says PHP is running.
I am now baffeled. I tried Notepad++4.7 save the file as *php, I also tried a trial version of PHP Desinger Pro which the script/file I created does run on it's own internal server apparently and says "Hello World" like you would expect.
Any ideas? I have read some things that hint to needing to modify the php.ini-recomended file and download som other patch for some php5 dll's?

[Wiedmann]

same if I try localhost/helloworld

You mean http://localhost/helloworld.php

[blazerfan]

Man I am learning how every little thing makes a difference.

I am so used to calling up websites not files and that was it the whole time.

Thanks I feel like an idiot...
I wasn't typing in the whole helloworld.php I was just typing in
localhost/helloworld