My new graphics card (GEforce 1650 super) suddenly stopped working and shut down my PC. I tried another but same result. The PC now only runs if there is no card in the slot. The wifi card sometimes works but stops after a few minutes. I can use the computer as long as there is nothing in the graphics card slot. I don't know if the problem is the PSU (550w) or the Mobo. The whole unit is less than 2 years old but I am still running Windows 7. Can anyone point me in the right direction please?