Webpages loading incorrectly

So here is my issue. When I load certain webpages (like kotaku, ign.. others) they load up either all disheveled (like the css didn't load or something like that) or some of the pictures didn't load up or perhaps a video or two. Then I hit refresh and it loads up perfectly fine the second time. Now this only happens on this computer, which is running Vista x64 Ultimate and it isn't the network adaptor because I have tried 3 different ones with the same result. It isn't my anti-virus (running McAfee Enterprise Virusscan 8.5i) because when I disable or uninstall it it still happens. It has nothing to do with my router or modem because the other computer on my network (XP machines) work fine. And it isn't a case of it being the browser (at least I dont think so) as it happens in both Firefox and IE7/8.

Okay, I think that about covers it all, if not just ask. Thanks for any ideas you can provide because I'm at my wit's end.