I use Windows XP prof which incluides also a PS Telephone. Until yesterday I used ANtiVir XP but now I can not call anybody on PC Telephone (PC toPC) My firends can call me, and we have a good connection, but I can not call them, I think it must be a bareer, which must be opened, but I don't know how, Please help me - I am only a user, so please make a step by step introduction