You can use the AppEnable method of the IIsWebDirectory object to reinstate a Web application definition that was previously disabled with the AppDisable method. If the application specified was not previously deleted, it will be reregistered with MTS.
IIsWebDirectory.AppEnable
<% Dim DirObj Set DirObj = GetObject("IIS://LocalHost/W3SVC/1/ROOT/MyAppDir") ' Enable the application at this directory DirObj.AppEnable %>
AppCreate, AppDelete, AppDeleteRecursive, AppUnload, AppUnloadRecursive, AppGetStatus, AppDisable, AppDisableRecursive, AppEnableRecursive