Internet problem SpeedTouch 716v5

Hello! I am using speedtouch 716v5 for my wireless network. I can connect to the router with cable and use internet with my macintosh, but not wirlessly. Neither can my PC. But my PC and Mac do both connect and show connected to the right wireless network, but i cannot get the internet on. Whats wrong? I really need wireless... Especially on my PC!

Thanks.

Ps. If i go in on the routers settings page (via cable) it shows that both computers have been connected wirelessly