I need to reinstall a client...

Hello,
I need to reinstall a client. If I format the hard disk and then reinstall a new operating system and after that the pro version of Avast, the server will give to it a new licence… I suppose I will lost the licence of the last operating system.
How can I backup (add it back to the server) the licence on my old system BEFORE deleting it ?
I hope I’m clear…
thank you for your help !
Mirus

well
where is it that you see the licenses go down?
if it is in ADNM then u must delete the old computer from ADNM and u will get the license back (i think)