**Symptoms:**

* When the computer is running, it randomly freezes and requires an hard reset. This happens both when using intensive applications (games, compiling) or just browsing the web.
* The freezing happens on both of my operating systems: **Win 8.1 x64** and **Arch Linux x64**.
* One particular freeze on **Win 8.1** happened while I was talking on TeamSpeak to a friend. After 1 minute I was able to continue speaking to my friend, even if the screen was frozen and nothing else seemed to work. The only thing I could do was literally speak to my friend through TeamSpeak. Alt-F4 wouldn't close TeamSpeak either. During the whole time the screen was frozen.
* After rebooting, sometimes nothing happens (the PC is on, though). I sometimes need to turn off and on the PC multiple times to get anything to display on the screen (the screen stays off otherwise, as if there is no input arriving to it).

**What I have tried:**

* Touching everything inside the case with the PC on. Tried touching RAM, GPU, SATA cables, etc. Nothing happened.
* Checking temperatures during stress/non-stress periods. They seem fine.
* Checking event logs/kernel logs. Nothing there.

Any idea what the problem could be? I suspect it is the GPU, because of the "TeamSpeak freeze". But honestly, I'm just shooting in the dark.

Info:

[lspci -v](http://pastebin.com/npPZbEPM), [lshw](http://pastebin.com/9m7dbuHv)