I am having some trouble with (I suspect) my wireless router. It's connected to the internet with a regular lan cable and has a static, public IP address. Our two home PCs connect to the router with regular lan cables, plus there's a laptop which connects over Wi-Fi.
diagram: Internet | | <- isp-supplied cat5 ethernet cable | D-Link D300 ...wifi... laptop / \ / <- cable -> \ PC1 PC2
The PCs and laptop are behind NAT and share the router's public IP. The router is a D-Link D300. PC1 is used for online gaming and I'm experiencing frequent "connection dropped" errors when playing Battlefield 3, StarCraft 2 and the Diablo 3 beta; but not with TeamFortress 2 or the Tribes Ascend beta. The issue goes away when I remove the router and connect PC1 directly to the ISP's cable. I have also tried disconnecting PC2 and the laptop, leaving PC1 as the only machine connected to the router - doesn't How can I diagnose what precisely the issue is?