1) exchange the router for the same make and model to verify it's not a router hardware issue
2) exchange the router for another make and model to verify it's not a PC issue.
Do not purchase this router. There are serious problems in the firmware, for which there are currently no updates available from Linksys. When you start using the administration web interface, it eventually stops working, and all computers on the network lose their connection. My router is brand new, and I can't even switch back and forth between the "Basic Setup" and "Status" pages more than a few times before the router completely hangs.
Linksys tech support has only one solution: reload the firmware and completely reconfigure the router. This takes at least an hour each time, even for experienced network administrators, and is not really a viable solution since you're just loading the same version of firmware over and over again. Thanks for nothing, Linksys.