Question about using the licence after reinstall operating sysyem

Hi,

 

I would like to purchase Norton 360 21.0 - 3 Computers, 2 year item (really wanted 2 computers), before I do I would like to ask the following questions...

 

I annually reinstall my hdd, clean install. Would I be able to use the same licence again without problems, regardless if I download iso or dvd.

 

Would I be able to put the iso in external hdd when I reinstalling my OS and re use it again?

 

Assuming it's iso file when I purchase the item

 

Thanks for any advice