Some ideas based on your post/description:
It is very possible that the management/support software necessary to run your videoconferencing system resides or is installed in the PC based router that got burned. When you replaced the router with a NetGear, you simply provided an interconnection/distribution/forwarding/sharing of your Internet access to the different PCs of your firm but nothing to replace the server/management software for the Polyscan System. You have replaced only half of the PC based router - the router only, hence you have Internet acces but no video conferencing which is software managed which was installed in the PC half. Additionally, Polycom uses online Product Activation which might be necessary for your system to start working again.
Depending on the model of the Polyscan System that you have, it is also possible that you simply have to reconfigure the network settings of your Polyscan' System to match the new IP address of the Netgear (which might be very different from what the burned PC based router was using before). I understand that Polycom have several models (or series as they term it - PVX, TPX, RPX, VSX, HDX, and others). Would you pls post back with the series/model number that you are using?
Have you tried discussing your concern with Polycom Support
? They might be in a better position to address this.
Hope this be of some help/idea. Pls post back with the Polycom system model that you are using.
Good luck and kind regards.