One is running Win7 and one is running Win8.
I have an external hard drive that I could load it on, I'm just not sure the licensing permits use on more than one computer and if it does, does it matter what Windows version I'm running?
the paid licences are to person and can be installed on multiple machines so long as they are also the buyer's personal PCs. In your case yes there wouldn't be an issue so long as the laptops in question are yours.
Thanks Nergal!!