website default page not found

Hi

I have IIS7 installed. I have a few folders under the wwwroot folder. I cannot open the default.asp pages on any of the folders for example I type in localhost/folderName. It sends me to this url http://www.localhost/folderName with a not found error. Why is www prefixed to the localhost url? The other pages from the website show up, just not the default.asp page.