Browser Defender is a plugin. You can manage your plugins via support, my account. When it is a plugin, it runs silently with IE.
It runs as a service to update as necessary. I would leave it alone unless you want to uninstall it. It takes little resources and I would recommend to keep it.
If you decide to uninstall it, you do so via add/remove programs. It will not affect SD per se. It will reduce the IE protection against bad web sites.
Buscar en complementos de firefox, si se quiere deactivarlo
Browser Defender by ThreatExpert, a SiteAdvisor Alternative