If you share your computer with your kids, then you have to make sure that they do not access any inappropriate content available on the internet. You can either set the DNS servers to OpenDNS Family in your computer and perhaps your router, or you can use a software like Surfblocker in your Windows PC. It can be used to restrict access to the internet on a scheduled time basis, you can allow or block websites and restrict the permissions of various programs to access the internet.
In the Surfblocker window, you can select Block Everything to completely block all the internet access. If you define some exceptions after blocking the internet access, then only those websites and services will be able to access the internet.
Another option is to Block harmful content which blocks all kinds of content that is considered malicious, harmful and inappropriate. You can define which type of harmful content you want to block from the settings. There is a big list of harmful categories that you can choose from and block the unwanted websites.
If you do not want just about anyone to access the internet, then you can set a password lock on the internet. This way anytime you want to access the internet, you can enter the correct password and use it. This is useful on a shared computer if you want to limit the use of the internet only to a small group of people.
The software can also help you if you want to limit the daily bandwidth limit, daily usage limit, the hours in which you want to be able to access the internet, etc. This way you can control when you want to access the internet, when you want to block it and for how long you want to access the internet every day.
You can download Surfblocker from https://www.surfblocker.com/.