"Put pc together 2,5 years ago, haven't touched it since."
PCs need a monthly cleaning if you are to avoid a big yearly cleaning. Since you didn't touch it in 2.5 years, it's time to open it up, dust it out and replace all heatsink compounds. When that's done you don't put the cover on but start it up and check fans.
If it's still dead, watch this video.
Searching forums couldn't find my exact answer but made me suspicious it could be psu.
Randomly all outputs from pc shuts down(monitor, keyboard, mouse, internet, also power button for pc) only thing that keeps working is dvdrw opening button and fan speed regulator. Pc seems and sounds as always.
So the problem showed up like 2 days ago. Have happened when playing smhg or just browsing web. First day it happened like 4 times during the day and today only once so far. Only way to shut it down is to pull the plug. Starting it up it has stayed the same also other times, then i have pulled out everything and plugged it back in but one time it didn't work, the other did. So that feels very random what changes that.
Put pc together 2,5 years ago, haven't touched it since. As i planed to reinstall before, after the first day that occurred i did, but nothing changed.
pc specs :
CPU : AMD FX-Series FX-8320 SAM3+OX FD8320FRHKBOX
Power Supply : Cooler Master ATX 2.3 Thunder 600W
Memory : Crucial Ballistix 8GB DDR3
Motherboard : Gigabyte GA-970A-UD3
Video Card : MSI GF GTX660 2GB GDDR5
OCZ Vertex 3.20 120GB SATAIII VTX3-25SAT3-120G.20
Seagate BARRACUDA 7200 1TB
Thank you in advance.