Buying Windows 7 - Cheapest option?

use a different product key for each machine,

example: machine 1 has windows 7 ultimate on it, so you use ultimatre key 1, machine 2 has ultimate on it also so you use ultimate key 2, if however machine 1 crashes and needs to be reinstalled, then reuse key 1 to activate it

once activated, its linked to your motherboard, unless you uninstall from the original machine,

in the example above: machine 1 has a hard drive failure, and you go out and buy a brand new pc to replace it, you can install key 1 back onto this new machine because you only have 1 pc running on this key

imacken said:

severedsolo said:

once activated, its linked to your motherboard, unless you uninstall from the original machine,

So this is different to the 'normal' situation then? Normally, as far as I understand it, you can't 'uninstall' a Windows product key. Each key is linked to particular hardware, and if that hardware changes by too much, then a phone call to MS is required.
I don't see how you could 'uninstall'.

sorry i didnt make myself clear there, that is actually what i meant, but MS define a "new computer" as a new motherboard, however if the key was no longer being used on said machine, you could reactivate it on a new one, with a call to MS,

OEM keys on the other hand, are tied to the machine for life and are non transferrable

I would not worry about the # of installs and activations that you are going to get. I can pretty much assure you that for your own personal use...you are not going to run out. I've never heard of instances were Technet users simply ran out of keys and activations with their subscriptions.