New system freezing constantly

RonXD

Honorable
Jul 11, 2013
10
0
10,510
Hi, I'm new to this forum so pardon me for not living up to the standard here.
I built myself a new PC around 1 month ago. it's really new. It's an fx-8350 with 4 GB of RAM, running windows 7 home basic 32-bit. My motherboard is the gigabyte 970a-ds3. I have a 600 watt cooler master thunder power supply and a xfx HD 7790 graphics card.(And a 2TB WD HDD)
Now my problem is that sometimes under load the computer just freezes. And i'm not talking about the usual freeze. Basically there is no power to the keyboard/mouse. The monitor just keeps displaying what it was displaying the moment it went haywire. Nothing works except a reboot. (Or pressing down the power button).
Details: It happens even if my system just started up after several hours. It mostly happens whenever Steam tries to update itself or under gaming load. It's also happened when trying to install new programs. My temps seem to be fine. Staying under 70c even under load, or atleast that's what HWmonitor tells me. I'm using the stock cooler that came with the processor. And here's a funny thing: when the system first freezes, the mouse seems to getting power from the usb port(the light is on) but the keyboard clearly doesn't get any power. Now if I unplug and replug the mouse then the mouse doesn't get any power anymore.
I'm at a complete loss. I have no idea what maybe wrong. It runs fine for hours without significant load. So can anyone help me, please? Thank you.