A couple of things to try, if not already done so:-
Try installing and using an alternative Web browser, for example
http://www.opera.com
If the problem persists, then try starting Windows up in 'Safe Mode' which will load a generic default Screen driver. If the problem is no longer present that would indicate a windows system or Graphics driver issue:-
- Power-on Windows and before Windows starts to load continue pressing the F8 key repeatedly in quick succession to eventually display an options menu where you can select 'Safe Mode with Networking'