Description: What is the new feature Secure Boot built in with new Windows 8 machines?

Windows 8 PCs purchased today and in the future will have the Microsoft Secure Boot feature enabled. Secure Boot prevents any "unauthorized" operating systems and software from booting on your machine. This feature is built into the UEFI of your motherboard, which replaces the traditional BIOS. When you start up your machine the UEFI will check what software is trying to load which normally will be the Windows boot loader. If the boot loader isn't signed by Microsoft it will not be allowed to load. This is how this feature will keep your system safer as it will not allow any rootkit or another malware program to hijack your boot process and load up with the operating system.

If you are looking to run any non Microsoft Operating system, such as Linux, you are able to go into the UEFI and disable Secure Boot entirely or add the required certificates.

For more in-depth technical information here is Microsoft's Post on Secure Boot:
http://blogs.msdn.com/b/b8/archive/2011/09/22/protecting-the-pre-os-environment-with-uefi.aspx