NIS 2010 5 user pack

I am using NIS 2010 5 user pack.  I have already installed it on 5 machines and in mynorton login it shows it.   If I decide to completely unstall it from one machine and reformat the machine and install NIS 2010 on it again will it allow me to authorize or will it say I have exceeded my 5 ysers.

If I can reinstall it is there something special I need to do i.e. unregister one of the installations or similar...

 

thx