Question Both GPU won't work on my pc but it works fine in others

[GilSmoke]

Alright, so first of all my two graphics card are

GTX 460 SE and RX 580 4GB RAM

first, when I was working with my academic project I turned off the pc so I can sleep, tomorrow I tried to open the pc it won't work.. So I tried to clean every corner and edges of my computer then.. I opened it again nothing happens. I bought an 8gb ram because I thought the problem was my ram.. But it still didnt work.. Then, after a week I bought a graphics card which is my latest one (RX 580). My psu is not compatible with my latest gpu cost it use 8 pins(pci) while my previous psu had only 6, so I bought another psu.. Lastly, after several times and attempts my gpu still won't work even tho I have already tested psu together with gpu with my friend's pc.. The thing is, the onboard gpu is working fine (I used dvi cable)

I need your help regarding to this post.. Thank you very much

Edit:
Psu: topower 700 watts bronze
Motherboard: foxconn w/ 1155 socket
Os: w7
Hdd: 500gb
Ram: 12gb
Chassis: lucoms

 

[rgd1101]

full system spec? include make and model of the psu

 

[GilSmoke]

I've tried to uninstall the drivers using the onboard gpu as display but it totally went wrong.. The system malfunctioned and it leads to the erasure of the data and hdd itself. I am not able to use the hdd anymore.