Security Tool is a fake spyware remover with an impressively generic name even in terms of rogue anti-spyware names. This parasite enters the system without the user's knowledge or consent, usually by employing the use of various trojans. Security Tool might also convince you into downloading it by using the browser hijacker Sitesecuritytest.com, which is a fake online scan. Security Tool uses misleading advertising to trick users into purchasing it's so-called "licensed version".
The easiest way to remove it is to boot your computer to Safe Mode with Networking.
Go to www.malwarebytes.org and download the free version, install, update and run Malware Bytes
Once complete select "Remove All Unhealed" and restart your computer.
HKEY_CURRENT_USERSoftwareVista Antivirus 2010
%User Profile%Local SettingsTemp
%Documents and Settings%All UsersStart MenuProgramsSecurityTool
%Documents and Settings%All UsersApplication DataSecurityTool