P8Z68-V LX working VERY SLOW on Windows 7

Hello,

I have a strange problem. I bought a new computer:
Motherboard: P8Z68-V LX
ProcessorL Intel(R) Core(TM) i7-2600K CPU 3.40 Ghz
NVIDIA GeForce GTX 560
64-bit Operating System (Windows 7).
Apacer SSD 59 GB.

I wrote all the drivers but computer still working VERY slow. I tried to find aswer on the internet, but I didnt solved this problem and I don't know what to do.

What I have to do to solve this problem? What decisions should be will made?

Thank you.