Step 2:Make sure your all other tabs in browser and other services in the computer are closed.
If possible for you then delete all cookies-cache and browsing history from your browsing
Step 3: While chatting on Facebook go to Start -> Run -> cmd
:After Opening command Prompt type netstat-an command and hit enter.
- Now you will get IP address of all established connections there.
- Note all the suspicious IP's and trace user using IP address tracer or you can shutdown computer using .That's it