We have researched the problem, really, people are faced with the fact that after downgrading back to Windows 7 flies activation. Find answers that Microsoft product support services, most likely, your copy of Windows was either OEM or pirated. This answer does not inspire confidence, but nothing more.
How to restore Windows 7 activation?
What are the outputs of situations?
1. you can try to remove the key from the Windows registry on your system. If somehow you can learn and now key is the only way. Other ways is to look in the documents, which were supposed to stay after purchasing the system, we do not see.
2. you can use non-activated version. This is absolutely nothing prevents, unregistered version has no restrictions in use and is capable of working over the years. Considering that the support of the main version has been discontinued a year ago and now it cannot be officially buy is not so strange option.
3. Use the Activator. Windows protection mechanism is pretty simple, and it already has facilities that can make your copy of “activated” without any problems. It is enough to check for soft request “windows 7 loader”. We do not recommend this option, but this is the easiest and fastest way to forget about the “problem”. Especially considering that buy Windows 7 product keys is no longer supported.
Why not suitable Windows activation key?
In addition, it is important to understand that after rollback version could change. For example, if you roll back a version was installed with SP1. In this case, available in your system registry, the license key is not suitable for her. Microsoft said that windows 7 pro product key if you still want to get a license in such a case, you have to seek it from a third-party vendor OEM versions of the system, which may be somewhere else. In this case, we again return to the third option, as the easiest way to solve.
How do I know whether to use the Windows key on another PC? The system windwos 7 product key sale was reinstalled, but hardly in the hardware, therefore, changed the motherboard buy cheap windows 7 product key or not is irrelevant. Important only the version of the operating system. In this case, you can try to install another version of Windows 7 Ultimate — for example, without SP1.
But I would, at the scene of both users, just not really thought hard about with these licenses.