Days ago I had a problem on one of MDT”s. There were installed OS images for some Windows 7 systems without SP1. Because I use the ImagePatcher PowerShell script to offline update all images, and there is no way to install SP1 with offline updating, I tried to delete the images and update new ones directly from DVD.
In that moment I had a problem with task sequences, because they lose OS images to install.
This problem can be solved very easy, with few clicks. You must open the desire task sequence and go to the tab Task sequence. You can find there the task “Install operating system”. In this task you have just to browse the right system you want to install.