I know, that if you search in google for "user virtualization", the related results are for Vista's user account control.. Well, that's not my problem or what i'm looking for. I've being testing Returnil, ShadowDefender, Sandboxie and many solutions that are quite relationed for what i'm searching. My problem began when I was really tired reformatting and reinstalling one, two, three and even six times my PC, because the main problem was that my brothers like to install software, use it once, and hten left it installed in the system, making it slower and slovwer by every program they want to "test". So I've decided to use Returnil, so they can install without the problem of uninstalling and leaving garbage in the disk and in the registry, keeping the PC performance up. But as always there is no perfect solution...my brother find out the "password issue" of Returnil, and reseted the password. With ShadowDefender my problem was about burning CD/DVDs, I can't burn anything with the protection up. Sandboxie is more oriented to application isolation, so it only covered just a part of my problems. That's why I'm here...looking for recommendations about software that can: -First of all, separate each user of my PC with his own enviroment of installations, so my brothers can screw up their user account, but not mine one. That's what i'm calling "user virtualization". -Second, that the program begins before the system, like Returnil of ShadowDefender. -Third, that the program leave the "base" installation of my windows untouched, and that all the changes or modifications be done to "virtual disks" or whatever it can be called, keeping the performance up and the file structure of the base disk intact. So, would anybody can suggest a program that can do that!? Thanks in advance. David Ulises PD. By the way, I was trying Altiris SVS with no luck, now i'm trying to test ThinApp and others. See ya.