As a Microsoft Registered System Builder, with Licensing credentials - I can
categorically state the following:
You must purchase a New operating system because the motherboard is not the
After an OEM software license has been installed on a PC, the license may
not be installed on another PC. However, the entire PC may be transferred to
another end user along with the software license rights. When transferring
the PC to the new end user the software media, manuals (if applicable) and
Certificate of Authenticity must be included. It is also advisable to include
the original purchase invoice or receipt. The original end user cannot keep
any copies of the software.
Generally, you may upgrade or replace all of the hardware components on your
customer's computer and the end user may maintain the license for the
original Microsoft® OEM operating system software, with the exception of an
upgrade or replacement of the motherboard. An upgrade of the motherboard is
considered to result in a "new personal computer" to which Microsoft® OEM
operating system software cannot be transferred from another computer. If the
motherboard is upgraded or replaced for reasons other than a defect, then a
new computer has been created and the license of new operating system
software is required. If the motherboard is replaced because it is defective,
you do NOT need to acquire a new operating system license for the PC as long
as the replacement motherboard is the same make andmodel or the same
manufacturer’s replacement/equivalent, as defined by the manufacturer’s
warranty.