It may be that when you try to connect your PC to the internet, the system notifies you of an IP address conflict.
This may happen when two computers on the network are trying to get the same IP address. Indeed, most routers are configured for DHCP, which assign IP addresses automatically.
To solve this problem:
Click Start/Control Panel/Network Connection
Right-click on the connection > Properties
Select "Internet Protocol (TCP/ IP)" > Properties
If the "obtain an IP address automatically" is checked and you still have this problem check the bubble "Use the following IP address".
Enter the IP address, Subnet Mask, Default Gateway (depending on the range supported by your ISP).
Example: Assigning the IP address when using a Livebox
Enter the IP address: 192.168.1.12 (or any other address in the following range: 192.168.1.10 to 192.168.1.19)