WAIT BEFORE YOU DO ANYTHING ELSE!!!
Getting a valid key is quite simple!!! First, open the activation dialog, choose the Activate By Phone option...it should give you a number to call. You will need his original product key (no worries, both his and yours will be activated fine afterwards). When prompted, provide them with the product key (or activation key or whatever it tells you to give them) and when they ask how many computers it is installed on, simply say ONE. You will then be provided with a key that you enter into the activation dialog box. Click OK/Apply/Whatever and you're both good to go!! I've done this a million times with multiple versions of all different Microsoft OS's and it's actually quite painless.
If you want to know what this technically is doing, here's the details. Microsoft allows 1-3 activations to process regularly. After it hits the "limit," you simply need to call them and follow this process. This is because someone may be reformatting their computer once a year and they would have exceeded their max. for activations. As long as you tell them it's only on 1 computer, they'll generate a new key for you every time. I have my personal copy of Win7 64bit installed on 6 computers (simultaneously and all receive windows updates perfectly fine) and my 32bit copy on 10+ computers (that's the one I let friends use if they need a free copy).
If you have any problems, just post here!
Make sure you do this before the activation period ends! Otherwise it will be a pain in the butt!
