See the following FAQ (Do I need to activate Windows after making a hardware change?): http://windows.microsoft.com/en-US/windows7/Activating-Windows-7-frequently-asked-questions Hope this helps.

We started getting "Windows needs activation" messages on 1 PC. This PC was inherited from someone so I have no documentation on it; it was home-built. I expect eventually this Windows 7 will stop working, then I'll have to do something. What is the sequence of events I should expect? I have a pack of OEM 64-bit Windows 7 installation pkgs but I shouldn't have to re-install anything, right? Can't I just enter a new key right there where it tells me how many more days I have? (I expect if I wait long enough Windows will force me to enter it!) What is the proper procedure? Thx all RG

Hi RG, When you get the "Windows needs activation" message, you need to active it. You may refer to the following KB article to activate the system: Activate Windows 7 on this computer Regards, Sabrina This posting is provided "AS IS" with no warranties or guarantees, and confers no rights. |Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

It is a 64-bit version so I will of course want a 64-bit key. It has Enterprise on it but I may not be able to buy that flavor. To remedy this I intend to buy a new copy of Win7 here and phone the key over to the location where the PC is. Can I use ANY unused 64-bit Pro or Ultimate product key for this PC? Is the "Product ID" (as shown on the System Properties page) the same as the "Product Key" we are talking about here? Thx folks

If your PC has Windows 7 Enterprise on it, forget it. That's a Volume Licensing edition which can't be activated by "any" key (activation by KMS normally, "Key Management Server" for Volume Licensing customers). As you have some OEM packages, format your harddisk and install one of them (Pro or Ultimate, as you like). It seems you have keys for that; unfortunately, you must re-install all when you do that. And no, the "Product ID" is a value derived from the "Product Key" but not identical with it.

If your PC has Windows 7 Enterprise on it, forget it. That's a Volume Licensing edition which can't be activated by "any" key (activation by KMS normally, "Key Management Server" for Volume Licensing customers). As you have some OEM packages, format your harddisk and install one of them (Pro or Ultimate, as you like). It seems you have keys for that; unfortunately, you must re-install all when you do that. And no, the "Product ID" is a value derived from the "Product Key" but not identical with it. THAT is a major bummer. I guess now I know why we were given this machine! Is reformatting really my /only/ option here? The machine is now in use with programs installed and live data, etc. So, what I understand now it that at the point where activation does whatever it's going to do to block me from the PC "buying a key" will not be an option. Am I hearing that there isn't in a non-destructive answer to this? Can't I install Pro (for example) over the present install?