How does the activation process work?

Apologies in advance if this is a dupe.  I've searched through the forum, but most of the commentary is along the lines of: I lost my key how do I reinstall.

 

My question is more: how does this work so I can decide if it's appropriate in my situation to purchase the product?

 

I have a number of XP machines for which I need to either renew my current vendor's software or move over to another (in this case possibly Norton).  This looked like the one to beat so I did do a purchase online, but when I went to do the download I didn't get a download link - it was an install from the DL manager.  This concerned me since I saw the 60 days to download this unless you buy extended download support message.  And my intent is to upgrade these to Win 7 in the next few months.  So if I don't have the software to reinstall I could be hosed.

 

So I went to chat, and got a rep who told me the trial would work OK and it would prompt me for the product key.  So I did an install and I didn't get the request for the key, it just completed, and showed the original key that came with the download.  And looking at my account online I saw a logged activation.

 

I got on chat again and got another rep who told me it was because I was upgrading from 2009.  When I told him I wasn't he said it got the key from the registry.  I now know it's from a text file nested in Documents and Settings (should have looked here first), but I did a registry search and it didn't come up so at that point I was getting a sinking feeling that I might not get an informed answer.  So I just asked for a refund, which I will say they didn't really put up any argument on, which is different than the Symantec I remember from years back anyway.

 

But here's the thing.  How many activations will process on a product key for 3 PC's?  IOW, if I install on 3 machines, and then need to reinstall on those same machine after I've blown the OS away in a few months is it going to say fine or am I going to need to go through support to get the old activations rolled back?  I see a generated code for the activation online, but is it doing it a la Microsoft where it looks at the characteristics of the system and as long as it's fundamentally the same box it goes ahead? How does it know that I already installed once on this machine if the old key file doesn't exist any more?  Or does it just ding me after 3 activations and say that's all you get?  Doesn't sound like it, but I'd like to be sure before I plop down the cash.

 

II may hold out for another month or so till the old licenses actually expire and I'm closer to doing upgrades.  And just go with a freeware option for a while until I know I'm going to be leaving it on for a while and then do a repurchase.  I know I'm probably the exception to the rule here. Just didnt' feel comfortable with proceeding even when I couldn't figure out it worked and neither of the support reps seemed to actually know either.