

However, Windows XP does require product activation too. For example, PC computers from branded OEM (original equipment manufacturer) is activated out-of-factory, and most hackers and pirates go for volume licensing (commonly known as VL or VOL) version of Windows XP Professional which when installed with a volume product key (VLK), does not require user to activate again online or by phone.

Windows XP has less stringent Windows Product Activation algorithm compared with Windows Vista.
