If you are using an mdb file nothing is designed to do this. If you are
using an adp file with SQL server you can use the SQL server agent.
The way I would do it with an mdb file would be to have a form and use the
OnTimer event. Set the event to run every 5 seconds and the write some code
to control the execution of your macro. Open the form hidden when the mdb
opens. Note that the mdb obviously has to be open in order for the macro to
run.
You can use the Windows Task Manager for this. The Command Line for the
scheduled task will be something like this...
"C:\Program Files\... PathToAccess\Msaccess.exe"
"C:\PathToDb\MyDB.mdb" /x NameOfMacro