Hi, I am trying to install Windows 8.1 Pro 64-bit on to my HP TouchSmart 600 that was previously running a non-genuine Windows 7 64-bit. I installed it from a bootable usb-drive using the software Rufus and the installation window worked. I did the custom installation where I deleted all partitions then clicked on new for my hard drive installation. Then, I pressed format and next which installed the OS up until its first automatic reboot. It then goes to the black windows logo loadup screen with a loading circle. After about an hours it shows the error: Your PC couldn't start properly After multiple tries, the operating system on your PC failed to start, so it needs to be repaired. Error code: 0xc0000001 I've tried reinstalling it multiple times but it just ends up the same way. I've tried repairing it and refreshing it, also the reset option where it deletes all your personal files too, but it still gets stuck in the loading screen. When I try to use automatic repair/startup repair it gets and error soon after saying it could not repair. I've used this same process before on a PC that was running Windows 7 Proffesional which was also non-genuine but worked and is still working perfectly. Any help please?