Windows freezes sometimes w/ new i5

[KillMHz]

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..

 

[theveterans]

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.

 

[OldMX]

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