So my PC has been freezing up after ~1 hour of use so I decided to use Windows 8's Restart function to completely uninstall everything and reinstall the OS. During the reinstall process something failed and I was either given the option to try again or to turn off my PC. I tried to reinstall again but it failed immediately. So then I just rebooted my PC, but now I'm getting the message that I do not have an OS installed on my computer and will either need the installation disk or a USB with the installation files. I only have my Win7 installation disk (I upgraded to Win8 via download). Do I just reinstall Windows 7, or find a way to get a Windows 8 installation disk/USB?