What is exactly the processor or graphics behavior when you try to install Windows or Linux?
Have you tried updating computer BIOS?
Please bear in mind the graphics hardware is part of the processor itself. It might be defective because you are saying everything works when you put a video card.
I fixed the issue. Problem was that the haswells are so energy efficient that older PSU can't handle that and they malfunction. I overclocked CPU, iGPU and deactivated some power saving options in UEFI and everything works!