Although the ability to display file that have no extensions was available by default in IIS 5.0, Microsoft has removed that default option from IIS 6.0. To re-enable the ability to display file types that have no extensions, follow these steps:
Click Start and select Programs, Administrative Tools, Internet Information Services (IIS) Manager.
Expand the Web Sites branch, right-click the Web site for which you want to enable no-extension files, and select Properties.
Select the HTTP Headers tab and click MIME Types.
Click New. You’ll see the MIME Type dialog box.
In the Extension text box, enter a period followed by an asterisk (.*).
In the MIME Type text box, type:
Click OK, then click OK again to display the Web site’s main properties page.
When you restart the Web site, you should be able to see and open files that have no extension. (To restart the server, right-click the Web site in IIS and select Stop, then select Start.)