Hi! I am reading your problem regarding you have same IP Address with someone. If you have your own router, I am thinking you're using a non-secure network. I would suggest to reconfigure your router by starting all over again.
Shutdown your computer, your router and modem. Then start with your modem, once the light is stable, turn on your router and connect the UTP Cable from modem to Router, connect another UTP Cable from router to computer and start the configuration. I am telling you this, to enable to setup again your network and make sure you put a password to your router so that nobody can access your system. Good luck.
Hope this simple instruction can help you.