Tannywheeler -

Q: If you unknowingly bought a counterfeit, how would you know?

The short answer is that when you connect up to the Microsoft site to get the program updates that you need, Microsoft will be able to tell if your program is counerfeit. If a valid license is necessary for the update you request, they'll tell you.

Wouldn't it act like a real one, mostly?

A counterfeit copy can be made to run, intitally, just like the real one; but will not be able to qualify to get the updates needed to keep it up to date.

Microsoft currently will give you what they consider the Critical Security Patches even if you have a counterfeit copy. This is because without the patches your machine is a danger to everyone else who runs a Windows system, and to some extent to everyone who communicates with it regardless of what OS they use. It can be infected, and will infect others, unless a large percentage of users are kept up to date. Without the security patches, your machine can easily be used by others to do malicious things, often without your knowledge, that are harmful to everyone.

Additional updates to the system, that address performance issues or fix "operating bugs" are available only to those who verify that their copies are legit. Just as running a 10 year old Linux system, with no updates, would not be "efficient" when most others have more current systems, running "original WinXP," which is now about 10 years old, prevents you from getting all the joy and fun that others experience.

An additional concern for those who might have counterfeit copies is that most counterfeits are "OEM" versions. Microsoft does not provide technical support for individuals with OEM versions. The OEM manufacturer is responsible for providing that support. As Microsoft finds OEM makers who are counterfeiting, they tend to disappear - often abruptly. This often leaves the holder of a counterfeit OEM version with no one to provide support, should it be needed.

If your counterfeit was made from a legitimate OEM copy by someone other than the OEM manufacturer, the OEM maker can identify it as a counterfeit just like Microsoft can, and probably will refuse to provide support for it.

John