MS just pissed me with its "upgrade" key restriction, because last thing I want to, is mess after old OS. So I did this nice combo: 1. Installed W8 Pro VL on clean HDD (VL didn't asked for key for obvious reason) 2. Activated it using mooo KMS (this is optional, I just did it for fun) 3. Changed DVD from VL to OEM/Retail/(Burned from Windows Upgrade Assistant) 4. Runned SETUP.EXE, entered "upgrade" key and installed W8 Pro (with WMC, but that is defined by key itself) non-VL by "Upgrade" I've checked the files on HDD and they are same as clean install of non-VL... ...protocol of 2nd installation just reports that 99% of files was just skipped, because the content of source and target file was same ...or do you know easier way? Used ISOs: 1. en_windows_8_pro_vl_x64_dvd_917699.iso 2. en_windows_8_x64_dvd_915440.iso or (for x32) 1. en_windows_8_pro_vl_x86_dvd_917830.iso 2. en_windows_8_x86_dvd_915417.iso To remove all backups from old system, just run cleanmgr.exe (with admin rights, otherwise you will not see all items) (in system32) and check all items in the list....