Firefox speed problem

Im having a problem with both Firefox and IE

Ive noticed that both browsers suddenly lost speed 2 days ago (for no apparent reason), and that since then they have been running at dial up like speeds. Downloads using the browsers also are extremely slow. Sites that used to load pretty much instantly now take a couple of minutes. Its not any extensions i use
(checked safe mode), ive deleted my cache, and my other internet based programs run fine and at their normal speed. what else could be wrong?

Thanks for your help.

mboro