wpmu dashboard has gone missing

The WPMU dashboard has gone missing from my site. I don't know how to set it up again. Please help. without it I can't easily set up the template for my multisite. The new plugins I installed today are also missing - one was a media share plugin and the other was the master template app. If I need to do something with wp_config you are going to have to give me detailed instructions as to where to find it and what to do because I'm not a webmaster - I'm a herbalist.