Hello,my pc now is running win8.1 but the hdd is crashed so it doesnt work efficiently anymore,i would like to ask if i can install win10 directly on the new disk without having to install 7/8 first.
Yes, you can. However, you may want to wait until the official release of Windows 10. If I'm correct, a Technical or eventually Consumer preview of the OS cannot be upgraded to the official release without the loss of all data on the machine's hard drive or ssd.