Windows freezes sometimes w/ new i5

I've formatted my PC 2 days ago, but since yesterday my PC is going crazy. For example, when I'm watching a film, or write on forums, CPU Usage & HDD Usage go to 0% and my PC freeze.
No, i can move the mouse pointer over the desktop, but every crash/block and my CPU/HDD remain at 0%.
My PC:
Intel Core i5-4670K
HDD Wester Digital Caviar Black 1TB
RAM 8GB G.Skill
HD 4600 integrated
D-Link DNA-556N Extreme
and other devices..

It might be that the HDD power saving feature that stop HDD from spinning and won't spin back. Use high performance power plan and see if it helps.

Check hard disk s.m.a.r.t. status with crystal disk info