Everything was working fine, then all of a sudden, there was no activity to one computer in the network. It says its connected, but I cant access websites, and the other computers in the network are fine.
I had a similar problem when I set up my network. It turned out that after 8 hours of trouble shooting that the firewall had been blocking every bit of data that went between the computers. The connection showed up as a healthy and fast, but like you said, no data was getting through. Check your firewall settings and see if that helps; it fixed my problem and could have saved me 8 hours if I had thought of it earlier.