Sorry to hear that's happening.
A couple of things come to mind...
Have you checked to ensure your display driver is up to date (from the web site of the maker of your video card)?
Have you tried clearing your entire Photoshop preference set to defaults? To do that, press and hold Control - Shift - Alt simultaneously immediately upon cold-starting Photoshop. If you get the keys down quickly enough - and you have to be really quick - it will prompt you to confirm deletion of your current preferences, which will lead to the establishment of a fresh default set. If it does not prompt you, you haven't been quick enough to get the keys down.
-Noel