That's correct you have to copy it from your opk kit to your WinPE CD or to a network share. Normaly, after typing in the reg key the setup Program copies the necessary files to your harddisk and return to the command prompt. after that you have to exit winpe. type exit in winpe and remove your winpe source (i.e. USB Stick, CD) Hi,kyor Thanks for your help. Now I can complete my winpe UFD. By the way,at first I typed the following commond %SOURCE%\i386\winnt32.exe /syspart:c: /unattend:%SOURCE%\i386\WINNT.SIF After the computer reboot, the setup program asked me to put "windows xp sp2" setup cd into the cdrom. So I used /makelocalsource and /tempdrive:c: parameters,the full commond is %SOURCE%\i386\winnt32.exe /syspart:c: /unattend:%SOURCE%\i386\WINNT.SIF /makelocalsource /tempdrive:c: the unattend setup went on successfully, just like it run from unattend setup CD. Is it possible run a unattend Xp setup under winpe 2.0 ram disk on UFD without copying all source files to the Hard disk?