HELP!! Need a script for DUMMIES for a simple login/register feature

I know very little html and am more of a designer, but my programmer has let me me down so I have to take this on myself.

I want to include a very common feature where visitors register to my site, so I can collect some information and contact details from them, then they can access hidden pages of the site and receive some exclusive download links by email, allowing them to download content (only once). They can then login each time they visit with a userID or email and a password.

My host supports almost every scripting language.

I've been told PHP is what I need, but I know absolutley nothing about it. My host said there is templates for such a simple script out there on the net for free but I'm being passed from pillar to post with scripts for much more complicated and rarer scripts than I need.

Hope you can help.

LB