Here are some steps you can take to fix a security certificate error on your PC:

1. Check your computer's date and time settings: An incorrect date and/or time can cause a security certificate error. To update your date and time settings, open the system tray on your computer, right-click on the time, and select Adjust date/time.


2. Check your computer's internet connection: If your internet connection is weak or intermittent, it could lead to a security certificate error. To check your connection, open your browser and try to access a secure website, such as your bank or another secure website.


3. Check your browser's security settings: If your browser security settings are set too high, they can cause a security certificate error. To check your settings, open your browser and click on the Settings icon. Then select Security and ensure that the settings are not set too high.


4. Verify the website's certificate: When you visit a secure website, your browser will check that the website's security certificate is valid. If the certificate has expired or is not valid, a security certificate error may be displayed. To verify the website's certificate, right-click on the page and select Properties. Then, check to ensure that the website's certificate is valid.