WampServer

All of a sudden with no changes to wamp at all, I type "localhost" into the address bar in IE7.0 as normal to bring up the wamp homepage on the local server and I get a mesage in a popup message box saying that it has to open in a new windows and a file explorer opens showing in file format all the folders and files in my root directory. the wamp executable is running but i don;t know why it is not working. Can anyone help?

thanks

Neil