The same happened to me and the person will try to intrude by finding an open port.
If you have a good firewall, you should have nothing to worry about.
You can test your firewall for leaks using this free online tool:
The best is to be stealthed when online including chats and online exchanges.
Last, if you really want this person off your back is:
1. to turn off your modem.
2. Click on start,
3. Click on run
4. type cmd and a black window will open
5. Type ip/config release
Do not reopen you modem for 3 hours and the ip by which the hacker is tracking you by will not be yours anymore. There are faster ways to change an IP but in this case it is the safest.