IP CHANGE

Hello,
I have problem with hacker hack my PC that I normally use static IP 192.168.1.1.
I don't understand why my PC is down and after start up I can not use the LAN communication via IP address that I set above.

So could you please help me how to protect if hacker want to change or delete my IP?
Hacker can login and delete my IP address?If yes please advice how to protect?

Thanks & I hope to recieve your answer soon.