How to move wordpress blog under IIS 7 sub-folder [closed]

Question

I have installed wordpress under wwwroot/mydomain.com/wordpress and bind it to mydomain.com port 80 under IIS 7.

Then I change to bind wwwroot/mydomain.com to mydomain.com instead and change site url in wp_options to mydomain.com/wordpress.

But when I try http://mydomain.com/wordpress I get 404 error from IIS. Why ?

Note: I didn't change web.config

<configuration>
    <system.webServer>
        <rewrite>
            <rules>
                <rule name="wordpress" patternSyntax="Wildcard">
                    <match url="*" />
                        <conditions>
                            <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
                            <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
                        </conditions>
                    <action type="Rewrite" url="index.php" />
                </rule>
            </rules>
        </rewrite>
    </system.webServer>
</configuration>