I had a little, slightly annoying problem that was an easy fix but I didn't understand why it took place.
I have a several folders in ../wamp/www/- and in one of them I had a file, that I had created, named index.php. When I clicked on the other directories I could browse through the normal list where I saw all the files, but when I opened the folder where the file Index.php was it executed immediately and I never saw what was in the folder. Instead I had to manually change the url to open other files in that directory.
I deleted index.php and half expected it to run some other .php-file in that directory, but didn't.
I'm aware of that there is a index.php-file in the www-directory (the comments in French though), which clearly is part of the WAMP system I downloaded, but having seen tutorials where people use index.php I'd have expected someone to mention this potential problem.