You would have to uninstall v15 and install v14. You will NOT be able to open any files that you saved in v15, though.
There are a few things to check.
First, graphics card. What do you have? Are the driver current.
Second is DirectX. SE uses OpenGL for rendering the graphics area, the other stuff runs Windows-like commands (I don't know exactly how it works) that use DirectX. I think QuickPick is one of those DirectX displays, just like tooltips, icons, etc. You should at least have DirectX 9. You can tell by going to Start --> Run and typing in "dxdiag." The DirectX version will be towards the bottom of the general tab.
Do you have SE View Options set to Graphics Card or Backing Store. Run on Graphics Card mode if you video card can support it.
Anything else running in the background on your computer that may affect graphics performance: SETI, animated GIFS, transition effects, etc.?
Give us some more information on what you're running and we can try to troubleshoot this problem.
--Scott
For some pleasure reading, try FAQ731-376