Windows 8 & 8.1 can be clean installed from a flash drive without any other software being needed. You just let the download create the flash drive and that's it. That worked last week on my desktop pc with a uefi. For my notebook, which doesn't have a optical drive. I copied my Windows 8 dvd on my desktop pc to a flash drive. That method also worked on my notebook with a uefi. SecureBoot is working on both pc's. For the notebook, after I ran Windows Update, so 8.1 would show up in the store, 8.1 was then installed. No issue's what-so-ever with both method's on either pc.