I had a Dell OptiPlex with i5 4590. I had to get tmotherboard because it went faulty. And since the old motherboard was replaced the original power supply with that desktop was not compatible with the new one so I bought a cheap power supply (big mistake) and cabinet. Been using for months now no problem, but now recently the computer started shutting down on it’s own. So with my previous experience I reset the cmos, replaced memory sticks, cleaned, checked cables and tried to reset the PC. However, it now shuts down even more quicker. I have found a tattern to it, it shuts down when i try to access the hard disk (install windows from uefi usb setup, or boot up the old hard disk which has os installed) i started the desktop with no hard disks connected and only the uefi setup and left it idle and its not shut down for half an hour now. But I’m confused because both the hard disks lead to shut down? So am I right if I say the power supply killed my hard disks? Or there can be some other reasons like motherboard problems?