starcraft 2 connection issues

I recently got a new computer and installed sc2 on it. When I try to log into battlenet it says that I'm not connected to the internet check your connection. I'm connected but interestingly when I open a webpage using a brower I suddenly connect. This needs to be done for everything in battlenet. I triend reinstalling and it managed to work just fine during one game and then when I joined a second game I began to lag and my computer shutoff. When i rebooted and played again, the same problem at the beginning occurred and continues to do so. If its port forwarding issues I'm on a Siemens speedstream 4100 B and I'm not sure if I can even forward ports on it. I tried to turn off the Microsoft firewall but that didn't help either. Not sure what to do.