"auto-executing" Excel macro's

I have an Excel template with external data from a midrange system. I automated the weekly pivot report in it by saving it as a template. I want to go one step further and let the midrange schedule a pc command starting the template and executing a macro. Starting the template is ok, but does there something exist in Excel like an "AutoExec" macro (like in Access) ? I want the weekly reports to be made fully automatically (and if it's possible Excel can be run in the background)