Hi all, My apologies if this is a repeated question; I am at my limit with computing today and have been scrolling through forums to find people with similar issues as I have. I had installed Windows 10 TP from Windows 8.1, and after realising what a mistake that was, I tried to revert back first to 8.1 then to 7. The "rollback" wasn't an option, and every installation technique I tried did not work. After much thought I decided to try to install Windows Vista. Unfortunately, each time I tried to install the OS, it reverted to the TP. In the Command Prompt I formatted the drive that contained TP and Windows, and made a boot USB drive with Windows Vista. I can boot the computer from the USB drive and the Windows Vista installation begins, but upon choosing a drive to install it to, it says "Windows is unable to find a system volume which meets its criteria for installation". After Googling this phrase, there is an article from Microsoft that outlines to make sure the HDD is a higher boot priority, or to remove the USB drive during boot up and to only insert it after Windows Install starts. I have reconfigured the BIOS and made sure the HDD has a higher priority than the USB drive, and the same issue occurs. I obviously cannot boot the computer without the stick because there is no information on the HDD to which to boot to. Any insight / help would be great!