If you are paranoid about computers, or Windows, or especially Windows 10, or even none of those and just about security, here is a good read. Click or tap for The Paranoid's Survival Guide.
But if you are paranoid about the Cloud, click or tap for Whats With all the Cloud Paranoia?
Then, if you want to "fix" Windows 10 particularly, click or tap for "Fix" Windows 10. Try not to overdo it, but do what you need to do to use Windows 10.