A friend of mine has a wrt54g router with just one computer using the wireless connection. He left all settings default. A new neighbor moved in next door to him and was using his wireless for free . So I was helping him set up some security measures. Everything went well with one exception. We used wep as he has g and b mixed. That worked but when I turned on mac filtering and clicked on edit mac filters the screen just flashes and the window for entering the mac numbers does not come up in order to type in the numbers. Kinda acts like there may be a problem with the router. It's a version 3 router. I've tried everything I know and would appreciate any suggestions.