bekin modem router and netgear switch

Hello everyone, have conected a Netgear FVS318 switch to a Belkin N wireless modem router to increase wired capacity, everything works fine until i set up wireless security on the Belkin modem. I then lose internet on the wired PCs, Im sure its something simple, but i'm quite new to networking problems, any ideas?

you can try out the Troubleshooting for the Belkin modem that has been mentioned here and see if you are able to solve the issue or not.