thanks May I respond to aspects of your note first? The media I used to supply the original Windows files is a genuine MS Windows XP Home edition disk - part no x0833941. Thinking about what happened I wonder if the way I started the rebuild process was a factor. I started the pc with the cd in a drive but it did not boot from the cd. Instead once Windows was running I started the installation process. Thinking back what I had meant to do was boot from the cd, then using the blue screens get to the point where the existence of a previous version of Windows is discovered and take the option to upgrade? . One of the Acronis files requested was tmntr_2k.sys. I searched the web, found a reference to what to do. This said find, on another pc, tmntr.sys, copy on to a floppy, rename to tmntr_2k.sys and insert in the pc being rebuilt. I was then able to tke the Browse option, selcet A; and the file was found. The same happened with the second Acronis file. An issue with the viaagp1.sys file is that when requested the keyboard and mouse are locked .