All current versions of Windows (Vista,Windows 7 and Windows 8) require activation, including copies bought from Computing Service Sales.
Normally activation can be done over the internet. If you do not have a network connection you can select activation by phone and call Microsoft. You will get on-screen instructions to follow.
You will need the product key from the Microsoft sticker (on a new system the sticker is likely to be on the case, if you are upgrading it will be with the upgrade media or box) and the activation code displayed on screen.
Windows activation may need to be done within as little as 3 days after installation or you will end up in Reduced Functionality Mode (where you just get a screen with a 'phone number and a reference code to use when you call).
Details on how to activate Windows if you bought your copy from UIS software Sales:
Last updated: June 2014