WAMP server Problem and Correct way to install PHP and MySQL???

Hello everyone, I have installed WAMP server on my PC. Then I have installed the MySQL and PHP software by downloading them from the site. The PHP programs I have written used to work fine but when I tried to connect to the MySQL database or create a new database using the PHP programming nothing happens in the browser. I do not know what happened. After several attempts I finally uninstalled the MySQL and PHP programs and then when I tried to connect to the MySQL usin PHP it worked fine I do not know the reason for this. Can anyone tell me what the reason is? Further more I would like to install PHP and MySQL along with a server like APACHE. But I do not know where to download the APACHE server from. Also When I install PHP and MySQL how do I link PHP and MySQL so that they work in tandem. Would be great if anyone can clear these doubts. I know that these are very basic questions but I am a starter. Thanks, Sashi