For record purpose only,

Lenovo ThinkPad OEM Key:
Windows 7 Professional : 237XB-GDJ7B-MV8MH-98QJM-24367
Windows 7 Ultimate : 6K2KY-BFH24-PJW6W-9GK29-TMPWP
A qualified BIOS with SLIC 2.1, and the Lenovo OEM certificate are necessary to activate the OS.
One can import an OEM certificate if the system is originally installed using a clean retail DVD.
(Download the file, change the extension from jpg to rar, then unzip)

BIOS SLIC2.1 + OEM Certificate + Retail Version OS = OEM OS.
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Lenovo/IBM ThinkPad OEM Key
Windows XP Professional: HCBR8-FGC2K-RY7BM-HM3KT-BKVRW

Retail VLK Key
Windows XP Professional
Key1: R2TFR-*****-G392H-*****-K6WY3
Key2: JHKP8-*****-HTXBM-*****-CHONG
(Part of the key blacked out upon request for confidential reasons)
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Windows Vista? Forget it….