Between your computer & the internet is a connection device. Generally it's a modem box. Is it a dial-up service where you connect via the telephone line & the modem dials up when you connect (dial up means you can't use your telephone at the same time on the phone line)? Or is it Broadband where it also connects via the telephone & is permanently connected & frees up your telephone. Or is it a cable service. Some cable services will run with their tv service. Some are just for net use & will have a cable modem box.
What I'd like you to do is answer those questions & have a close look at your modem box to find out the brand & model. It might be blocking your service for p2p sharing use. We can unblock it but I need to know what model it is 1st.