Hi Charles,
There are two types of Activations.
1) First Activation and Reactivations (where
no Hardware was changed or any new hardware drivers
* were installed, that changed the Hardware ID of any of your hardware). This type can be done over the internet or by phone. (note: there may be a limit on how may times this can be done, but I do not know for sure)
2) Activation using a COA SLP key and Reactivation (where Hardware was changed or added and/or new hardware drivers were installed, that changed the Hardware ID of any of your hardware). This type can only be done by Phone.
For the purpose of Activation, Vista uses the Hardware ID, from the hardware in your computer, to identify that computer. If the Hardware IDs change enough (due to new Hardware or Divers
*) and you attempt to Activate over the Internet, our servers see that Product Key being used on a computer that has a different Hardware ID then the last time it was activated and will give the error "this product key is already in use by another computer". At this point, a Phone activation is required.
If I didn't answer your questions or if you need any additional information on activation, you can see the Vista Activation FAQs at
http://windowshelp.microsoft.com/Windows/en-US/Help/62088be6-3538-46a6-99fb-05e74aeb48b51033.mspx or call the Activation Call center (same number as when you Activate by Phone). They should be able to answer any of your Activation related questions as they have more indepth knowledge of the intricacies of Product Activation, then I do.
Thanks for your question,
Darin Smith
WGA Forum Manager
*Microsoft has found that some hardware manufacturers have started writing Drivers that change the Hardware ID of the hardware it controls. Microsoft is working with these manufacturers to minimize this from occuring in the future.
Attention Forum All Users: Please Do Not post your issue in someone else's Thread...Create your own.