|If he had any access at all he could be stalking you in some form. If you feel threatened then contact the local police. |
I doubt he is that smart but you never know. All sorts of companies offer tools to spy on people. He could have done any number of things.
The only way to be sure is to reload the OS from OEM media and be sure to change passwords on routers and maybe even email accounts and any that he may have access to.
Be sure to have a good security suite on your computer.
There are not too many ways to make a computer die remotely but I don't know what you have exactly.
Hang up and live.