I'm not sure what your problem is, partly because you haven't told us enough. How are your base station and router configured? Have you configured the base station OR the router to provide DHCP addresses, but not both? What kind of PC hardware do you have (processor type and speed, RAM, hard drive size, etc.)? What PC operating system are you using? When you "connect directly" through the router, what exactly do you mean? (Ethernet from your Mac to the router, and ethernet from the router to the PC?)