It sounds like you may be having problems with style sheets.
Often such a problem can be caused by browser settings, browser cache, or browser add-ons (particularly privacy add-ons like "Disconnect").
If you have any common add-ons or extensions in those browsers, try temporarily disabling them to see if that helps. Or try a completely new browser with no previous history as a test.
There was a problem in the UK regarding similar symptoms that turned out to be caused by a third party "child safe" setting used by certain internet service providers. In that case switching to another service provider or disabling the "child safe" feature allowed pages to load again until the feature was fixed.
