I agree with ch33zw1z. Start over and tell us *everything* you have, including all devices that connect to the network and how they connect(wired or wireless). I wasn't sure from your posts if you have both a router and a standalone switch or just a router with a built-in switch? Another idea I had was if you had a computer that might be causing the problem by being connected to the network using both wired and wireless interfaces. I get the feeling the problem is probably something software related in your desktop PC. Anything you installed after doing a fresh re-install could be interfering with the network. I've seen it happen. It could also be malware on the PC.