First things first. If you can use another PC and have space to recover the personal data from it, do it. Just use Explorer to copy out your stuff. Don't worry about the OS as that's easy to restore, you need to note what apps you have on it and locate install media or internet links to installers. Also a good idea to have a copy of your network driver to allow for a network connection for downloading updates/apps.
Then focus on hard drive health. Before installing a fresh copy of Windows you need to ensure that the drive is healthy. If you cannot run Seatools using the PC something is wrong. Try running the Seatools bootable media on another computer. If it loads okay it may indicate other issues with your PC. Use that USB/SATA adapter to use Seatools on the PC that loads Seatools properly.
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