My mom noticed that some sites weren't rendered correctly on the winxp box we've got (that I rarely use, but that's another story) and some were even not viewable at all.
One of the sites that aren't viewed correctly is www.resedagboken.se. The photos in the middle of the page is simply... not there. This happened in both firefox and IE (!!). I examined the page source and compared it to the page source on my linux laptop. The result is: the <img> tags for these images are missing on that computer -- they are replaced with whitespace.
I'm having a hard time thinking of anything else than spyware that could cause this... so I'm currently scanning it with ad-aware. Who knows what that poor box might have gotten on it.