I have been networking 2 systems for months now with no issues but suddenly it doesn't work. its a mac mini and a G4 500 tower networked over a d-link standard 4 port broadband router. nothing is wrong with any of the cables or any of the hardware. file sharing is turned on with both systems. I can access the mini from the tower but not the other way around. this seems so odd and I can't figure out the issue. when I click on the network icon it does nothing. shows nothing at all.. not even itself. I am a tech savvy guy yet I am totally stumped here. any ideas are welcome. thanks in advance.