what wifi card are you using i read and learned from experience that the wireless N card dose not tend work well with older computers but the wireless G card works very well on old and new
also have you tried one of these to get more Ethernet ports i use them with my web-servers http://www.maplin.co.uk/p/netgear-8-port-gigabit-ethernet-switch-a12gy i got myn much cheaper than this though
