browser downloads PHP files instead of server executing them

[smash]

Hi
I upgraded my PHP version from 4.x to 5.1. I followed the tutorials I found on this site and trustabyss.com.

I have mysql 4 installed and was in the process of installing phpmyadmin (according to the tutorial).

I have two problems now.

1: when I go to my phpmyadmin directory in my browser as per the tutorial i get this error:

cannot load mysql extension;
please check PHP configuration
and a link to Documentation.

I've followed the installation of PHP and phpmyadmin to the letter as far as I know.

2:I have various php files on my server. I have a directory of stuff that is just files I've written to practice php coding. When I open these files, for instance one that has the phpinfo() function or othere with simple math functions they all work. When I point the browser at an old phpbb install the browser tries to download the file instead of pricessing it as a script and giving me a PHP error message like when there is no connection to a DB or an undeclared variable.

Anyone want to take a stab at what might be happening here or what i might have done wrong?

[MonkeyNation]

[smash]

thanks.
I went and downloaded the configured package of php5 and installed it. Things seem to be working ok so far. I'll see what happens when I try to install my CMS