Using Windows PE as an Emergency Boot Disk (Windows Embedded Standard 2009)
If you make changes to your device that make the device unbootable, you can use Windows PE as an emergency boot disk.
For example, you might do this if you deploy an image to a dual-boot test device and you accidentally overwrite your test machine's boot.ini file with your image's boot.ini file. If you cannot start your computer, you can boot by using the Windows PE CD-ROM and fix the boot.ini file.
Boot the device by using the Windows PE disc.
After Windows PE starts, at the command prompt type:
Edit the boot.ini file as needed.