Find Dr.Web in the Finder. It is usually located in the Applications folder, which can be found on the sidebar of any Finder window. To find the application, you can also use Spotlight (the service icon looks like this: ). Then double-click on this application in the Spotlight window while holding down the Command button (⌘).
Drag the application to the Trash or select it and choose File > Move to Trash.
When prompted for a username and password, enter the administrator login and password on the Mac.
To remove the application, choose Finder > Move to Trash.