Spyware and anti-virus are both up to date and I scan regularly.
Shouldn't the distance from the exchange should have the same effect all the time, not just sometimes?
Router is straight into the phone socket and speed affects the desktop pc that is wired to the router as well as two laptops and a Mac that connect wirelessly, even if only one computer is in use at any given time.
It seems to be the entire web that slows down.