If reinstalling Windows 10 feels like too much, use these tips to troubleshoot and speed it up. Search for the ISO file by clicking 'Add Search Location' and choose the mounted ISO file. Select the target external drive and click 'Next' to go on. After getting Windows 10 installed, here are some tips to help get you started. Once it is opened, the inserted external hard drives will be detected. You can also use the media tool to upgrade from Windows 7 to Windows 10, following these instructions. If you don't see it, or it goes away too fast, I suggest consulting your manual for instructions.
When you first turn on your computer, there'll be a small line of text telling you which button to press to enter BIOS. The process for each computer (or motherboard if you're building a gaming PC) will be different. If it doesn't automatically boot to the drive, you'll need to reboot your computer into its BIOS firmware - usually done by pressing Esc, F2, or a similar key while the computer is starting up - and change the boot drive or 'bootmenu' to your flash drive. Your PC should boot to the drive, giving you the option to install Windows.
Going forward, if you need to install or reinstall Windows, you can connect the drive to your computer and reboot it. When the tool is done, click Finish and remove the USB drive from your computer.
