A Bootable Windows Preinstallation USB stick can be a useful tool for any PC fix-it guy's toolbox. Here's how to make one and use it for maximum effect.
As it happens, WinRE capability is available from only two sources: the Windows Vista install media and as part of the Windows OEM Preinstallation Kit (OPK), which is a toolset available only to registered Microsoft partners. This may also explain why Microsoft fails to document how to build a WinRE boot UFD and why Technet claims that the WinRE wim file must be named winre.wim and installed on a hard disk (it’s also the case that this is indeed the only way to failover to a WinRE boot image, which may have been more to Microsoft’s point here). But because so many people have Vista installation media and might prefer a speedy boot that takes fewer than two minutes with a UFD instead of waiting for the install DVD to produce the recovery console, we show you how to grab the WinRE windows image file next and fly in the face of this contention.
When you want to use your UFD to boot to ordinary WinPE, leave this file structure along. When you want to use the Windows Recovery Environment, rename boot.wim to boot.orig, then rename winre.wim to boot.wim. Only then can you boot into the WinRE console as shown at the beginning of the story (you’ll need to rename boot.wim to winre.wim and boot.orig to boot.wim to revert to the original WinPE environment). If you don't see a file named winre.wim in the \sources directory, then you know it’s currently your boot tool, so it should be easy to keep track of. On the other hand, you could set up another directory on the UFD named \images, and keep boot.wim and winre.wim in there. Then you need to only copy boot.wim into the \sources directory to get back to plain-vanilla WinPE. Or you can copy winre.wim into the sources directory, delete boot.wim, then rename winre.wim to boot.wim to use WinRE instead. This way, you always have a backup version in the images directory should you mess up in the sources directory.