Help! XAMPP is giving me problems.

I need your advice concerning a few issues I am having with XAMPP.
I really hope you can help me.
Every time I type “local host” in the Firefox URL bar, what appears is not XAMPP but what displays is IIS main page.
What I would like to is whether or not it is possible to have XAMPP displayed instead of the IIS.
The other issue I am concerned about is with the Apache in the XAMPP control panel.
Nothing takes place at all when I click on it.
I tend to think that this problem with the XAMPP control panel Apache results from an error in Port 80.
Is it possible to change the Apache port?
