virtualbox.org

A novice to virtualization, I started using WIndows Vista as a guest OS in October. I had to update Guest Additions after upgrading the Ubuntu host to 11.10 - the only way I managed to do that was by reverting to a snapshot taken before Guest Additions or any software had been installed, and installing the new Guest Additions from scratch. After that the MS Security Essentials antivirus program refused to validate the Vista OS. It is my understanding that this happens when several validations have been done within a short time period of one another, the new installation of MS Security Essentials would have been confused by the validation done before the upgrading of the host.
I'm switching to Windows 7, and I would very much like to use it as a guest OS, but I intend to also install it on another HDD partition in a dual-boot setup, to be used in case there was trouble with the virtualized system. Could the validation process of Win7 get confused by two successive installations, and interfere with the use of either installation? If such a problem occurs, is there any way to fix it, or get around it?

You should ask Microsoft this question. There are more things involved here than just the activation. You also have to follow the license rules they set and we're not a MS license expert here.