I have no idea about Windows Easy Transfer, but I do know a way to move the old Windows 8.1 to the new computer. First, you need to install and launch a software AOMEI Backupper Standard, backup system to NAS, then, use the PXE Boot Tool to start up the new computer, and when the computer started up, the AOMEI Backupper main interface will show on the screen. Here, you can do an
universal restore to restore the old Windows 8.1 to the new PC. Hope this could be helpful!