Hi,
First, you should make sure you have a fine cable and then you can use another computer to connect your router to test whether this issues
happened again.
If its, you should check your DHCP setting of your router or contact to routers manufactory for help. Also you can try to set a static IP address for your computer to see if the problem be resolved.
If its not, you may try as below methods:
Method 1
1.) Disable any Security or Firewall Software? Do you have one installed that's maybe expired?
2.) Disable IPv6
3.) Disable the IP Helper Service from Control Panel=> Admin Tools=> Services
Method 2
Start, All Programs\Accessories and right click on Command Prompt, select "Run as Administrator" to open a command prompt.
2.)In the command prompt window that opens, type type the following commands, each followed by the Enter key:
3.)Reset WINSOCK entries to installation defaults: netsh winsock reset catalog
4.)Reset IPv4 TCP/IP stack to installation defaults. netsh int ipv4 reset reset.log
5.)Reset IPv6 TCP/IP stack to installation defaults. netsh int ipv6 reset reset.log
6.)Reboot the machine.
Method 3
Call your ISP to make sure their network are normal
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