If you installed WAMP on a computer with IIS installed, there is a big possibility that both local web servers are using the same port, which is port 80. You can verify this by connecting to http://localhost:80/
When you are getting the IIS7 then this would mean that IIS7 is using port: 80.
You can configure your wamp Apache server by navigating to 'C:\wamp\bin\apache\Apache2.2.17\conf' if you installed wamp on drive C. Open the httpd.conf file using notepad (Warning: You should change your "User Account Control settings" at Control Panel\All Control Panel Items\User Accounts to "Never Notify" before you could edit your httpd.conf file)
On your 'httpd.conf' file look for these lines:
# Listen: Allows you to bind Apache to specific IP addresses and/or
# ports, instead of the default. See also the <VirtualHost>
# Change this to Listen on specific IP addresses as shown below to
# prevent Apache from glomming onto all bound IP addresses.
Change the last line to Listen 443
(From Listen 80 to Listen 443)
This is changing the port that your wamp apache server would use to port 443. Save the httpd.conf file and restart your wamp server.
After restarting verify the wamp server installation by launching 'http://localhost:443/
If you are seeing the Wamp Server Home, then you are good to go.