Internet access is carried out using a browser. Accordingly, so that no one except you can use the Internet on a computer, the password must be set on the browser itself. The process for setting a password will differ depending on which program you are using (for example, Internet Explorer or Opera).
If you are using Internet Explorer, launch it and open the Tools menu. Then click on "Internet Options", select the "Contents" column. You will see a window in which there will be a field "Access restriction". Click the Enable button. Now you just have to select the "General" item and set a password.
Those who use the Opera browser will have to do a little more manipulation. The fact is that it is impossible to set a password directly from the program settings (this option was in effect in earlier versions of Opera, now it is disabled). Therefore, additional software will need to be downloaded. The Exe Password program is quite common. It is designed to work with any version of Windows. To download it, visit the official website of the developers - there you will find a section called Download.
After downloading the file with the program, run it to install. Now go to the Opera browser. Right-click on its shortcut. In the context menu that appears after installing the program, the Password Protection item should appear, click on it. After that, the "Password Setting Wizard" will appear on the screen. Come up with your password and enter it in the field called New Password. Do not forget to repeat it in the appropriate field - Retype New P. Then all you have to do is press the Next button, and then Finish.
So that no one except you can access the Internet, you can also create several accounts on your computer and set the necessary parameters for each of them. In addition, you can restrict access using an anti-virus program. For example, in "Kaspersky" there is an option "Parental Control".