If your router is frequently disconnecting from the internet then you need to check the troubleshooting tips that are mentioned below -
Reset your router - By resetting the router, temporary bugs will get cleared and it will also force the device to reconnect to the web with a clean slate. Locate the Reset button on your router. Press the Reset button by using a sharp object like the paperclip and hold this position for 30 seconds. Restart your router after some time and hope everything will get normal.
Test Multiple devices - If after rebooting, you are still facing the same problem then you should determine the root cause of the problem as rebooting is only a basic thing that you can apply whenever your router behaves weirdly. Try to connect your mobile, smartphone, tablet to your router and check if you are able to access internet on them. If none of the device is getting online then the problem is related to ISP, so contact your ISP as soon as possible to resolve the problem.
Reinstall Network Card Drivers - If you are able to access the internet but your internet connection is not stable then delete the network card from your computer’s Device Manager. After this, reinstall the network card drivers so that you can stabilize the internet connectivity. Also, check the firewall settings. You can turn off the firewall or put it at minimum settings. If you have enabled port forwarding then set the DMZ as “enabled”.
Check Windows System Files - If the system files in your operating system are corrupted then definitely you will face connectivity issues. If the connectivity issues have started recently then restore your Windows operating system to the previous point. By restoring Windows to the previous version, internet connectivity issues will get resolved as the corrupt system files will get replace into good and non-corrupt files.
Hope these measures will help you to stabilize your internet connection.