Why is my internet going so slow?

I've checked the firewall, even disabled it. I reset my router. I've tried to reset my ip (ipconfig /release and /renew) but it doesnt change. My computer is connected via cat5 from my wireless router. The connection is on board and not a nic card. I uninstalled and reinstalled the driver. It was working fine just until a few days ago. There are no virus' or anything of the kind. I keep my machines clean. I have 3 machines on my network at the moment. However, I've installed a usb wifi stick and that connects fine and the internet runs great off of it.