You can use the AppEnable method of the IIsWebVirtualDir 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.
IIsWebVirtualDir.AppEnable 
 <% 
Dim VDirObj 
Set VDirObj = GetObject("IIS://LocalHost/W3SVC/1/ROOT/MyAppVDir") 
' Enable the application at this directory 
VDirObj.AppEnable 
%> 
 AppCreate, AppDelete, AppDeleteRecursive, AppUnload, AppUnloadRecursive, AppGetStatus, AppDisable, AppDisableRecursive, AppEnableRecursive