You can speed up or even eliminate 'stuck' images and text by setting the cache level to 0 (zero) in FF (and any other browser that has that kind of preferences). That assumes you have a fast connection, not dialup.
Has the Ethernet cable had any stress put on it lately?
Have you used it to hang wet clothes? Pulled any vehicles out of a ditch? Attach the anchor to
Sneakers fishing boat? That's the way most Ethernet cables go bad, in my research. However, those little tiny wire fingers can also get "bent out of shape," just like some people I know! It's usually less stressful on
you to simply get a new one. And maybe a spare, that should insure that you'll never have trouble with the new one.