WampServer

I am completely new to WAMP and I've been searching for a while, but could not find an answer.
I had IIS7 installed, but uninstalled it since I do not use it anymore. So I installed wampserver2.0.
Once installed, i installed the apache and mysql service. I made sure all services were ran and the icon was white.

I then type localhost on firefox and I got this:

You have chose to open ... which is a: application/x-httpd-php
from: [localhost]

So I tried IE8, and something similar happens.

Do you want to save this file, or find a program online to open it?
Name: localhost
Type: Unknown File Type, 6.29KB
From: localhost

Weird thing was, yesterday, I uninstalled wampserver and reinstalled it. Then typed localhost and a default wamp page appears. Then the next day (computer was left on, on sleep mode I guess) i tried localhost, but that download curse popped up again. I don't know what to do now.

Some info on my system:
Running on vista64, service pack 2.

Host file only says (includes #....)
127.0.0.1 localhost

I tested port 80:
Your port 80 is actually used by :
Server: Apache/2.2.11 (Win32) PHP/5.3.0

I've tried suggestions to add stuff to the httpd.conf file but that didn't seem to work. Things I added were AddType info.

Please help, thanks.

either your firewall/antivirus block wamp or you didnt run through localhost

to setup basic website, follow this
[blog.jlbn.net]

Have fun,

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Thanks for your response. I am a step closer.

I read the blog or what I can out of it--that site for me, is hard to follow since links are everywhere (and I don't think all of them work).

Anyways, I made 2 folders in c:\wamp\www as follows:
c:\wamp\www\project1 <- index.php and website files
c:\wamp\www\website1 <- index.html

So I restart all my services and localhost brings me to the wampserver homepage. I click on website1, I see my html file I created.

I then click on project1, and the "download curse" happens again. It tries to download the index.php instead of reading it. So now I assume, it has something to do with php options not properly set up?

My index.php are using the following tags:
<?php
.....
?>

Any clue?

Forgot to say, I don't have a third party virus scanner or firewall program. I do however have microsoft security essentials. I disabled the firewall that vista has. But no positive outcome.