First, open Activity Monitor and look for the Scanner Monitor entry. Select it and then click on the Quit icon in the AM toolbar. Next, open Accounts preferences, click on Login Items, then delete the monitor's entry from the login items list. Last delete the application which is in the Applications folder.
Uninstalling Software: The Basics
Most OS X applications are completely self-contained 'packages' that can be uninstalled by simply dragging the application to the Trash. Most applications create preference files which are stored in the /Home/Library/Preferences/ folder. Although they do nothing once you delete the associated application, they do take up some disk space. If you want you can located them in the above location and delete them, too.
Some applications may install an uninstaller program that can be used to remove the application. In some cases the uninstaller may be part of the application's installer, and is invoked by clicking on a Customize button that will appear during the install process.
Some applications may install components in the /Home/Library/Applications Support/ folder. You can also check there to see if the application has created a folder. You can also delete the folder that's in the Applications Support folder. Again, they don't do anything but take up disk space once the application is trashed.
Some applications may install a startupitem or a Log In item. Startupitems are usually installed in the /Library/StartupItems/ folder and less often in the /Home/Library/StartupItems/ folder. Log In Items are set in the Accounts preferences. Open System Preferences, click on the Accounts icon, then click on the LogIn Items tab. Locate the item in the list for the application you want to remove and click on the '-' button to delete it from the list.
If an application installs any other files the best way to track them down is to do a Finder search using the application name or the developer name as the search term.
There are also several shareware utilities that can uninstall applications:

AppZapper
CleanApp
Yank
SuperPop
Uninstaller
Spring Cleaning
Look for them at www.versiontracker.com or www.mackupdate.com.

For more information visit The XLab FAQs and read the FAQ on removing software.