NEVER ASKED FOR SERIAL

This happens with Adobe apps, start an app then wait 2 minutes then
go to HELP then ACTIVATE, if ACTIVATE is greyed out then there is no
need to input the serial. If ACTIVATE is available and DEACTIVATE is
grayed out then turn off internet and CLICK ACTIVATE and enter the 
serial if the serial box appears.

If you are concerned about this then;

Go to the CS5 LICENCE RECOVERY folder then the DLL FILE folder and copy the
32bit dll file and replace each instance of that dll file in your adobe programe 
directory, then if you have 64bit copy the 64bit dll file and replace each instance
of that dll file in your 64 bit programe directory.