Alicia, in your case using Windows Installer package, it actually doesn't installs anything on your computer, but runs the required applications/servers to start your moodle only.
Now you mentioning that your typed localhost and nothing happened? there must be something on the screen showing up or is it blank? if everything is startled from scratch, then typing localhost should start Moodle setup wizard on your computer.
also, if you have downloaded the windows installer package, then installing IIS is of no use, as this package already comes up with Apache as web server, so if you try installing IIS and on top of it starting this package, Apache wont get the required port 80 allocated to even work (you have to either uninstall IIS or change port numbers for Apache).
Now tell me where you stand?