thanks, bj-kaiser for your help, but it doen't work. I got the error bootmgr is missing! So then I tried to copy the file bootmgr from C:\Program Files\Windows AIK\Tools\PETools\x86 to the root of the USB key, and got the following error : Windows failed to start, file:\boot\bcd (an error occured while attempting to read the boot config data) after some searching the net i found this : I've been able to create a bootable USB key in the following manner: * Copy the folder "boot" from C:\Program Files\Windows AIK\Tools\PETools\x86 to the USB key * Create a folder named \Sources on the USB key * Copy the file winpe.wim or boot.wim to the \Sources folder on the USB key, and rename it to boot.wim if necessary * Copy the file bootmgr from C:\Program Files\Windows AIK\Tools\PETools\x86 to the root of the USB key * Install the Windows Vista Boot loader by running the command, with the appropriate drive letter for the USB key: bootsect.exe /nt60 d: Tried it, vista started to load, but stops on a dosbox "x:\windows\system32>wpeinit