There is no such thing as a "legit copy" of a Windows 10 installation disk or stick, since they are free to make, with the Windows creation tool. But you need a paid license key to install them.

This is not a monitor problem. Either the contents of the USB are not good (try to boot from it on another PC to see if it shows up to check that or make one yourself from https://www.microsoft.com/software-download/windows10) or something is wrong with the PSU or motherboard or CPU or RAM. Your task then is to find the faulty component or connection.