downloads keep stopping

Whenever I try to download files from the interenet, the download begins ok but stops after a short time, usually 0-10MB into the download. I have experimented with different browsers (IE7, IE8 and Firefox), with and without download managers, and with two different wireless adapters, but always have the same problem. With Firefox and Free Download Manager I have tried pausing and resuming the download when it goes wrong, this usually works a few times, but then it won't even resume.


This happened out of the blue. It had also happened once previously, but only went on for a day or two before correcting itself just as suddenly. The problem reoccurred a week ago and still going on now. Would be grateful for any advice.