Very NEW PC freeze after 2 days

Hey guys, i brought new PC finally, 2 days ago. But it seems it i have a problem now. It Freeze whatever i do, randomly, sometimes, it freeze in a row, sometimes, after 5-6 or more hours.
I did every test, it is fine, all drivers are update to date.

I have no idea what to do.
Edit. I found out that i have 250 V power supply

Here is my spec

Operating System
Windows 7 Ultimate 64-bit SP1
CPU
Intel Core i7 4790 @ 3.60GHz 33 °C
Haswell 22nm Technology
RAM
16.0GB Dual-Channel DDR3 @ 799MHz (11-11-11-28)
Motherboard
MSI H87M-E35 (MS-7846) (SOCKET 0) 33 °C
Graphics
SyncMaster (1920x1080@60Hz)
Generic Non-PnP Monitor (1024x768@60Hz)
2047MB NVIDIA GeForce GTX 750 Ti (Point of View) 32 °C
Storage
1863GB Seagate ST2000DX001-1CM164 ATA Device (SATA) 30 °C
465GB Western Digital WD My Passport 0740 USB Device (USB (SATA)) 27 °C
Optical Drives
WD Virtual CD 0740 USB Device
HL-DT-ST DVDRAM GH24NSC0 ATA Device
Audio
Realtek High Definition Audio

What is the Wattage of your power supply?

Hi,
This gpu requires a 300w minimum psu = power supply
EVGA GeForce GTX 750 Ti 02G-P4-3751-KR G-SYNC Support 2GB Video Card - Newegg.com

From post #1

I have no idea what to do.
Edit. I found out that i have 250 V power supply

Last edited by Boshko; 17 Hours Ago at 18:53..

If it's new, return it. A new computer should not have any problems.