It doesn't let me type anything on the Live Chat Window.

If you can't type anything on the Live Chat Window maybe you have problems with a security protection software from Comcast.

We found that Constant Guard security protection from XFINITY Internet doesn't let type anything on the Live Chat Window, in order to fix this problem you need to uninstall the Constant Guard Software

More information related with the Constant Guard security protection from XFINITY in the follow link : http://digital-qa.blogspot.com/2011/06/i-advise-against-installing-comcasts.html