If you have a legitimate Windows 8 ISO file, creating a QCOW2 image is straightforward. Here is the step-by-step process using a Linux host (Ubuntu/Debian/Fedora).
The actual physical space consumed on your host drive. Cluster Size: Typically 64 KiB; affects I/O performance. windows 8 qcow2
Inside Windows 8, open Command Prompt as admin and run: If you have a legitimate Windows 8 ISO