email threat - "they" had my computer password (and it was the CORRECT one!)

You need to change the password for every online account you have.

You should NEVER use the same password for more than one online account. If one service is compromised, you're exposed on every site where you use that password.

It was simply a phishing attack, you likely use a simple password that is easy to figure out and use it for a number of items including your e-mail. Work on using more secure emails and use a password manager such as 1Password to manage all of your passwords.

some breach of sites such as linkin and others a few years back gave them a lot of username passwords to use for this type of thing