Product Activation is supposed to prevent piracy and freinds from copying or borrowing software, but it's an annoying and completly worthless feature of Windows XP, TurboTax, Norton Anti-Virus and many other programs and games that forces users to call the company and register to be able to run it after you install it.

If you change hardware (such as a video card or hard drive) on a Windows XP computer many times, XP will force you to call Microsoft to register the OS again. It also unfairly forces users to buy 2 or more copies for each computer you own. The best thing is complain to the company and tell them you will not buy thier products anymore. Dont support companies that force product activation.
I couldnt run TurboTax this weekend because I had to call an 1-800 number for Product Activation - and the office was closed until monday morning!
by Whatever April 16, 2005
Get the Product Activation mug.
An anti-piracy scheme created by Microsoft which requires users to "activate" their copy of Windows or Office. Activation sends your product key and a unique hardware identifier to Microsoft, so they know that a given copy of Windows is installed on a given PC. If a user tries to install that same copy of Windows on another computer, they are blocked. Activation is usually done automatically over the internet, but can also be done by calling Microsoft and talking to a rep.

Product activation was designed to stop piracy. But the only thing it's succeeded in stopping is the installation of legitimate copies of Windows by users who rightfully own it. Activation often fails when someone upgrades the hardware in their computer (since the hardware identifier is different). People who pirate software can easily get around product activation by use of cracks and key generators.
When I reinstalled Windows on my computer, it failed product activation, because I had replaced my processor and video card.

I downloaded a cracked copy of Windows off of Warez and it doesn't even try to activate itself!
by computer_guy February 17, 2008
Get the product activation mug.