updated 01:20 pm EDT, Wed May 23, 2012
Boot menu redesign due to promised fast boot times
Windows 8 will have an improved pre-boot menu screen, to avoid constant reboots and stop the user from repeatedly tapping F8 or another key to interrupt the process before Windows loads. An MSDN blog post by Microsoft's Windows engineering team explains in detail how the system will work if the BIOS is needed due to a problem, and how to get to the same screen when there isn't an issue.
When something goes wrong during startup, Windows 8 will boot inside the Windows Recovery Environment (WinRE) instead of the desktop. The automatic fallover behavior detects if something is drastically wrong, for example if a PC is repeatedly reset, and displays the WinRE menus. Bringing the same screen up when there isn't an issue can be accomplished from the Start screen and the PC settings menus.
The new boot-interrupt has been designed with UEFI-based PCs in mind, due to previously seen fast boot times. Older hardware will still have the ability to conduct a boot-interrupt in POST.