Hi miekiemoes, hi Fatdcuk, Thanks for your replies. Under the present conditions, considering the provided information, I can only agree with your statements. Nether the less it is very strange that on booth systems of my pc (equipped with a plug-in module which enables to change the disk "C" when the system is shut down. I have two different disks, one with XP Pro 32 and one with W7 Ultimate 64). For both systems have observed a similar behavior. In fact I've observed that the process of windows update (in the hot phase, e.g. after download and before installation was stopped when the when «PUP.Optional.BundleInstaller.A» that had been detected by Free MBAM ("manual" quick scan) was put in quarantaine (and deleted). The example from W7 has been shown as information. For W7 when I wanted to restart I had the supplementary choice "Install the Updates and Shut down" or "Shut down without Installation of the Updates". I selected "Install the Updates and Shut down" but there was no Update installation. For XP the situation was a little more complicated because I had still remaining problems (PUP.Optional.Conduit.A) as I have detected it after the fact by a full scan. PUP.Optional.Conduit.A was apparently installed as I had installed DIVX. "Conduit" could be totally removed using Free MBAM. But also for XP when I made a "manual Quick Scan" between the download of Windows Update and the installation of Windows Update the Symbol "Update ready for installation" disappeared from "Information bar" (right side on the bottom of the screen) exactly when I removed the PUP which was detected. In November, when "Windows Update" will be available I will test if that phenomenon will occur again. In this test I will also include two other machines, both with XP Home 32. I will inform you about what I have observed. As I am not at home in the update period of November you will get this information a little bit later. I would be happy if your statement can be confirmed!