Error 500 (Internal Server Error) is a webserver related error , IIS in your case. As Carl mentioned, probably IIS is unable to communicate with ColdFusion properly. When you create connector during installation, you may get this type of error (not always). The best way is to remove the connector and follow the steps mentioned in my post
Mandatory update includes security certificate and Adobe recommends applying the same. Here is the Installation guide (http://help.adobe.com/en_US/ColdFusion/10.0/Installing/coldfusion_10_i nstall.pdf).
If you are still getting 500, please check the exception and application log. You may try removing the connector and checking the application then. This would help you narrow down the issue.
Regards,
Anit Kumar