If you notice notifications from Google Chrome regularly appearing in the corner of your screen. They will state that you have a virus and you need to run a scan for viruses. Many times, the notifications will mention or have a picture of a real anti-virus software (e.g. McAfee, Norton) regardless of whether or not the software is actually installed on the computer.

How to fix
What is happening is that a site was able to manage your Google Chrome site settings so that it is allowed to send notifications through Chrome. This is typically caused by completing a seemingly innocent CAPTCHA or request to Allow a site access to Google Chrome.
1. Confirm that the notifications are coming from Google Chrome by locating the Google Chrome name and icon in the notification as seen in the example picture above.
2. Locate the site name in the notification (Will be different than the one above)
3. Open up Google Chrome
4. Select the 3 dots in the upper right corner of the Chrome window
5. Select Settings
6. Select Privacy and Security in the left pane
7. Select Site settings
8. Select Notifications
9. Locate the name of the site from the notification
You can use the Search field above the "Clear all data" button to help narrow down the search
If you would like to delete all data associated with that site, you can click on the trashcan icon on the far right side of that site's row, then click Clear