start app at a certain time

I would like an application (eg explorer) to start at a certain time.

for example

 
(setq    Time     (substr (rtos (getvar "CDATE") 2 6) 10 4)
     );setq
 (if
   (= Time "1200")
  (startapp "explorer")
   )

However this code will only work if it is activated at 12:00

How can I make it so that the explorer will open at 12:00?

My guess is that reactors are the way to go?

Trouble is I know nothing about reactors - is there another way to make it happen?

thanks to any way who could help

cheers SF

Having another think about it - my guess is that a reactor would be the only way to do it. The event would be any action in Autocad eg a command, moving cursor, saving, auosave, etc. If there is an "event then the clock is checked. Can someone write some code that would do that please?

I will have to dissect it line by line to understand it.

Thanks