This will not let you steal Windows 7. It is merely a method of recovering / deploying what you already own and have payed for. I do not know if this is “legal” with the state of Microsoft licencing I think they could make anything illegal with the right lawyers.
First you need to locate the (something).xrm-ms file. This will be located somewhere in the recovery image or under the windows directory of a oem machine. This file is the certificate that validates the certificate / key that is stored in the EFI/Bios of the machine. Once you have this file you can validate / activate your OEM licence key against your bios.
cscript //B “%windir%\system32\slmgr.vbs” -ilc c:\windows\Setup\Scripts\oem.xrm-ms
cscript //B “%windir%\system32\slmgr.vbs” -ipk XYXYX-XYXYX-MV8MH-98QJM-XYXYX
The OEM key can generally be found in your recovery / installation image as well. Using this method you can use any install media to recover or deploy your OEM Windows 7 install.