Hi, cajunjunky & Neil:
Thanks for your replay.
In my case:
1. Any other maximized window ( explorer, IE or any other ) will cause the overlays problem. When I change the display mode from normal to fullscreen, or reversely, it can be correct. But in some media player, it doesn't work to change the display mode.
2. To cajunjunky: I think we have the same problem with different appearances. Some media players behave just like you said. I think it relates to the methods of different media players how to initialize (or how often to reset) the overlays render. VMR or sofware accelerate mode will not cause this problem, and maybe the difference between your systems is not the point of this problem. I'v adjusted my media players to VMR mode temporarily to avoid this problem.
3. To Neil: Here's a Very Important information: I'v done some tests. I opened a normal explorer window on the desktop, as usual it didn't cause the overlays problem. But when I put it's window frame outside the screen, just a little, it caused the overlays problem just as a maximized window. I'v done more times, and found that if I move both the left & top borders out of screen, it will cause this problem. A single outside border or other sets of outside borders did NOT cause the problem. (The sets of outside borders include double, triple and full sets of borders. In the double sets of borders, only the top-left caused the problem. In the triple sets, the top-left-bottom and top-left-right caused the problem. The four outside borders caused the problem.)
BTW: Nvidia 5200 display card with 81.98 WQHL driver.