The Digital River links are dead. Your only legal choice is to go to their new site and enter in the product key. Unfortunately, it hasn't worked for me so far. Once I got an error code saying that I would have to contact the manufacturer(it was a W7Pro key on a Dell desktop), and another time I entered a valid OEM W7Pro key and received absolutely nothing. No error message, nothing.
As far as W7HomePremium ISO working for all 64 bit flavors, I have discovered the hard way that a W7Pro 64 bit key will not work with a W7Home Premium installation ISO downloaded from DRivers.
Yes, if you burned a DVD you are ok, for now. But, as I discovered, once your installation DVD gets too many scratches and/or fingerprints, you won't be able to install. I was fortunate enough to make a USB installer key with W7HomePrem 64 bit ISO on it using Rufus before the MSoft takedown of Digital Rivers. Unfortunately I did not do the same for W7Pro. I'm going to try a W7Pro ISO from a buddy of mine, but if that doesn't work to make a valid installer key, then I'm stuck either using the DVD until it wears out or using a torrent copy(not my favorite either). This is such b.s. All they are trying to do is hasten the adaption of W10 so they don't have another XP on their hands.
BTW, I actually sold a laptop with Win7 to someone who was still using XP. I got some questions about admin rights today, and the guy eventually admitted he didn't know what he was doing. And this was a kid in his 20's, not some old fart like BMike.