When a computer boots, the Windows activation mechanism checks if the OEM certificate on the drive matches the SLIC table in the BIOS. If they match, Windows automatically activates without the user needing to type in a key.
To understand how these loaders work, one must understand the standard OEM activation process: SLIC (Software Licensing Description Table): windows 7 slic loader 249 22 hot
A "SLIC loader" exploits the boot process by intercepting the handoff between the bootloader and the operating system kernel. The mechanism generally operates as follows: When a computer boots, the Windows activation mechanism