HTTP Error 500.19 - Internal Server Error

Hi all
I hope this is posted in the right forum.
I am no developer, just someone trying to help a friend out. He has a business and gave me some asp files for his website. I rented a shared server account at HostGator and uploaded the files, however I receive the following when trying to access the site at: http://win.bergs.net
HTTP Error 500.19 - Internal Server Error The requested page cannot be accessed because the related configuration data for the page is invalid.
And further:
Detailed Error Information Module IIS Web Core Notification Unknown Handler Not yet determined Error Code 0x800700b7 Config Error There is a duplicate 'system.web.extensions/scripting/scriptResourceHandler' section defined Config File \\?\D:\InetPub\vhosts\win.bergs.net\httpdocs\web.config
I know nothing about this but would be thrilled if someone could help, paid or free I need to get ...