So upgraded from 7 to 8 and all is good except every few seconds a white box appears above the taskbar where the action center flag is, it opens and vanishes so quickly you can just see the outline and its defiantly a dialoged with a pointer leading to the flag but the content is not visable so what could be causing this and how to stop it?
I would suggest a clean install instead of an upgrade install. Upgrade installs always have the chance to be flaky.