OS: Windows 7
CPU: Intel Core i5 750
RAM: 4 GB Kingston DDR3 1333 CL9
VGA: ATI Radeon HD4770
HDD: Samsung 750 GB SATAII
Motherboard: ASUS P7P55D
First after install Windows 7 and install all basic drivers
, this problem occur. After fresh install K-lite codec pack, the problem was resolved. But following a few weeks, I try Windows Experince Index again and the problem recurrence.