Thanks, but i am just wanna know that if there is a way to use the data files of MSDN, all data file(*.chm) is on the disk, why we can't use?? Why we must re-install the MSDN, that's so boring to re-install it! If we can do it, just copy all data file to a disk and invoke these data at wherever we want, don't you think that's great? such as, win98,win2k,winXP and so on. I mean if you setup multi OS on your PC, and you need only install MSDN for one time, and then can use it under any OS you installed. Can this become true?:) Go go go, enemy sighted! Roger that!