So, where do I start. When I click on a menu, what I expect to happen is to see the menu expand so I can see all the options. You know, like every other program out there? Instead, nothing happens - until I move the mouse over the area where the menu was supposed to be, and then the menu appears the way it's supposed to.
Tool tips have the same issue. When I hover over a button or something, nothing happens. Unless I move the mouse and it happens to move to the same spot that the tooltip was supposed to appear in. Then I see the tooltip appear (usually very briefly).
One more example: I'll left-click to reposition the 3D cursor. Nothing will happen. If I sit there and wait, the 3D cursor will appear to remain exactly where it was before I moved it. Unless I, for example, rotate the viewport or do some other action, and then the 3D cursor will magically appear in the new location (where I left-clicked earlier).
I'm using Windows 7, and this has happened to me in both 2.76b and in 2.77. I tried both the 64-bit version and the 32-bit version. I don't have a clue what's happening.
Anyone? I'm just starting to get into Blender, and this is an increasingly major obstacle as I'm trying to learn some of the basics.