Browsing troubles

I have recently been experiencing strange browser behavior. Every once in a while, sites (including *,, and others) will show up without images or styling; just plain html (not code, but plain rendered html pages). It happens most often in Konqueror (my prefered browser currently), but just now it did the same in Firefox as well. I just launched Opera to see if it acted any different. The pages looked fine in Opera, but now they work fine in Konqueror and Firefox as well (so I don’t know if Opera actually doesn’t have the problem, or if the problem had gone away on its own just before I tried Opera).

I have tried clearing the caches but it hasn’t made a difference. Does anyone know what this might be?

This has very occasionally happened to me because of congestion on my broadband line. Does it happen at particular times of day, for example, when everyone is starting work or everyone has got home and is checking their email?

Come to think of it, I think it may be happening while I am upgrading my Factory KDE 4.