@xtp183, I think you are right, Qos Packet Scheduler is installed when you install with an original XP CD. @cumminbk, you are right, it is possible to install Qos Packet Scheduler with winnt.sif. But I currently have a lot of running machines, XP or 2000, without Qos Packet Scheduler because they were installed a long time ago with an unattended process (winnt.sif or Unattended.txt). Now I must deploy Qos Packet Scheduler on these existing machines because it's required by a new software (to deploy too). I have existing deployments means, logon scripts or other deployment software, but I don't have an unattended installation package to install Qos. So I'm searching a way to deploy it in an attended way on already existing running machines, something like a command line with silent switches, a batch, a script, or whatever... Many thanks for your replies.