Blank pages

This isn't exactly a Mac thing, though I suspect it may be: for the last week or two, when I click on one of those sponsored links (on a cream background) at the top of Google or iGoogle, all I get is a black page with a single white pixel in the centre. Thinking it might be a Firefox problem I tried Safari -- and got a blank white page. Same with Google Chrome. Normal links work fine, and ones that I use frequently, like Amazon, work even if they're in the sponsored section. So what's going on? (It doesn't happen if I use Yahoo as a search engine.) I'm on a 27" Intel iMac; my wife uses a 22" iMac and doesn't have this problem. . .