If windows doesn't boot, it may be possible to repair the install. But if you're comfortable installing windows on your own, you might find it easier/less time consuming (assuming you haven't spent ages customising/installing stuff on the existing install).
When you've repaired it or done a clean install with the 4TB drive unplugged, the partition on the 4TB drive should no longer be system reserved and you'll need to go back to the admin command prompt and run those diskpart commands again.
When you've repaired it or done a clean install with the 4TB drive unplugged, the partition on the 4TB drive should no longer be system reserved and you'll need to go back to the admin command prompt and run those diskpart commands again.