Activation key out of uses, need to do fresh install of Windows

I built my gaming PC about a year or two ago, since then it's been my main computer, not just a gaming PC, and has gotten filled with useless junk I no longer need. The GPU has also started to crash quite a bit recently (ever since I installed the new driver).

So I plan to do a fresh install, the problem is, the product key for my Windows 7 Home Premium x64 disk has been used the max amount of times (all product keys have 3 uses (apparently), I used this one on my gaming PC, the new family PC, and then on my Macbook Pro (however, I ended up having to reinstall it to my Macbook as I was messing around with rEFIt trying to get Linux on there alongside OS X and Windows 7 and bricked the thing (luckilly there's that recovery hard drive on there, so I can still use OS X))).

Anyways; is there any way to do a fresh install with this disk despite they key being completely used up?

I think it's just a normal retail version; as when we bought it I only planned to use it for one PC.

As for it being installed on only 3 PC's and no other yes; the only computers that I have which can even run Windows 7 are the 3 I've mentioned.

Oh; well then it's probably a family pack (as the two computers running Windows 7 now using the same product key are both connected to the Internet and it's never told me that it's not genuine or anything like that).

Then I've got no clue what I'm doing. :P
As I have it currently on two computers, but when I try to install it on my Macbook it tells me that it's not genuine each time.

*will try again however*

No; the box I have looks like this just without that white sticker on the front top.

http://www.winsupersite.com/content/...d75b515e04b1d2

However, that might be a box in the box (although I don't remember ever having a box like those ones you showed me and I doubt there'd be a box in a box).