If anyone thinks they know the solution, can they post clearly on how and what to disable so we can test? As far as I know there is no single page you can load to see the squares? It takes some time. Someone already tested this to affect Windows 7 so it is not just Windows 8. I have uninstalled Firefox 18.1 and have installed Firefox 17.0.1 and am still waiting to see the corruption. If Firefox 17 is clean and 18 is not - then that's something to go on. I am testing official Catalyst 13.1.