No internet to some programs

Hello, so i have some problems with inernet.
Well, first of all i have internet acsess, i can surf the webb in firefox and play games as normal.
The problem is that my computer is not letting some programs have internett like Msn, Steam, Skype, that sort of suff
I only use the windows firewall and norton antivirus, i have tried to turn off the windows firewall with no change.
And also i did not do annything before this happend and i have tried it at a friends house and its no difference so its not my router.
Please help me cuz its getting really annoying :S