Security essentials 2010 installs a fake virus scanner on your machine and blocks some processes. It also blocks access to the websites of some of the antivirus companies. It does this by downloading a Win32/Alureon component and another Layered Service Provider (LSP) component which monitors the TCP traffic sent by various Web browsers and blocking any traffic to certain domains.
Moreover, Security essentials 2010 charges you to scan and remove files on your machine, claiming the version you will have initially downloaded as a trial edition. This is contrary to Microsoft Security Essentials which is free for genuine Windows users.