Slow network connection at boot

I am not much of a network expert. So maybe someone can help me figure this out. I have an ATT DSL internet line with a Netopia modem and a Nertgear router. To the router I have an ethernet cable connected Desktop and 2 laptops that connect via WiFi. All systems run Windows 7 When I boot my laptops, the internet connects instantly. But when I boot my desktop (Dell XPS 8300), it takes at...