Nope. Windows Product Activation is a little more complicated. It depends what version of Windows you have, Retail or OEM, and the method chosen by the OEM.
If you have a retail version of Windows XP, then a Product ID is generated based on the product key and a 'Hardware Hash' generated from 8 hardware devices (each belonging to a different hardware category). The hardware categories are:
1. Display Adapter
2. SCSI Adapter
3. IDE Adapter
4. Network Interface Card / Network Adapter (including MAC Address)
5. RAM Amount
6. Processor Type (including Processor Serial Number)
7. Hard Drive (including Volume Serial Number)
8. Optical Drive
During activation, the Product ID is stored on the hard drive, and sent to Microsoft.
The motherboard is actually not in the list. However, components in the list (such as display, SCSI, IDE and network adapter) may reside on the motherboard, which explains why retail users may find that they need to activate after changing the motherboard.
If you have an OEM version of Windows XP (pre-loaded), then one of two activation methods is enforced, depending on the OEM who manufactured the PC...
The first method is a 'System Locked Preinstallation', where only manufacturer specified information from the BIOS of the motherboard is used, and no hardware hash from other hardware devices is generated. So, installing a different motherboard will require you to re-activate. But changing other hardware devices won't.
Alternatively, OEMs can choose to activate the same way a retail user would have to activate, and in this case, the OEM version of Windows XP will generate a Product ID using the Product Key and a hardware hash based on 8 hardware devices.
