trying to conenct to internet for first time, provider (plusnet) says all okay, BT says line is okay, must be my PC settings wrong - which ones should I be looking at please?
It's been a long time since I used a dial-up modem, but go into devices and check the properties/number your modem is dialling. It may be set up to automatically prefix the number with a "9" (or similar) to access an outside line.