now, IIS does not have something to do with that(Directory Listing Denied) because I myself have IIS and WAMP installed and running at the same time but on different port and even though they are running on the same port, that's not the error that is expected.....
The message "Directory Listing Denied" is specific to IIS.
Apache gives the message:
Forbidden
You don't have permission to access / on this server.
Neither of these are error messages. They occur when a webserver is configured to disallow directory indexes. (ie: you do not want to display your directory structure)
It is just a coincidence that IIS is configured this way, and it looks like an error. The actual problem with Apache is unrelated to the IIS message. But the message does show that IIS is using port 80 on the localhost. This causes Apache to fail on startup.
You should find the error message in the Apache logs. It should say that Apache failed to bind to the network address, and then it should have a "Stopping Service" message or something similar.
At this point you cannot tell if WAMP installed successfully, that is also unrelated to the IIS message. It is most likely that WAMP installed successfully, but only Apache cannot start, since IIS is using port 80 on localhost.
I think the best option is to figure out if WAMP installed successfully or not.
If WAMP installed, it should create icons depending on your choices: desktop icon, taskbar icon, start menu entry etc.
If you have any of these, start WAMP using it.
When wamp starts, it starts a status icon on the right hand of the windows taskbar. This means WAMP is running, but it doesn't mean Apache, or MySQL etc. are operational (though usually they are).
If you click on the WAMP status icon, it should give you a menu. If you get to this menu, then WAMP was installed successfully, you just need to configure Apache to work with IIS or remove IIS.
The other way to see if WAMP installed successfully it to find the list of services that WAMP registers.
On XP, and Vista, you can do this by opening the command prompt and typing in:
sc query state= all
See if wampapache, and wampmysqld are registered services, they should be listed. If they are not listed, then WAMP did not install correctly.
If they are listed, but their status is stopped, then you need to start WAMP. After starting WAMP, you most likely will have the wampmysqld (WAMP MySQL Deamon) running, but Apache will still be stopped since you have the problem with IIS.
Then you just need to configure Apache or IIS as mentioned. Then stop and restart WAMP, or just Apache, through the WAMP menu. Do this until you get the Apache Service running.
Then you should be able to access the pages served by Apache through the browser.
Sorry for the length of the post.