but people are just changing their password and using it again! I am sure that you have options where you can grab the re-package of the product key. I really don't know how long you have to wait to get another one. I would call your Windows dealer and give that still valid key that you re-purchased with the original activation code.
Windows 7 could be the most difficult Microsoft OS to activate in the last couple years. And it seems that Microsoft made activating even more difficult by changing how the product key is delivered and stored. If you have the limited number of activation codes, you will want to follow these instructions to activate Windows.
If a lost or stolen computer is connected to your network, and you disable the automatic product key distribution, the invalid product key can no longer be distributed. If you own your own service tag for a new computer, you must insert it for the computer to be activated. In contrast, with the downloadable product key, Windows 7 will only use the product key that you type.
If you are using the downloadable Microsoft product key, Windows 7 must be activated within the first six months of its release. After that, you can only use the one-time-activation (OTA) product key issued. d2c66b5586