Dell has a procedure to get a set of "backup" discs.  For US customers  Click Me       For other countries, contact Dell for your area.
I have a DIM 8400 purchased in 2005.  The system will not boot up. Error message “Windows could not start because the following file is missing or corrupt \windows\system32\config\system.”  Everything was fine until I allowed an MS  update. The next day, it would not boot.  The system came with no set of CD’s. Is it possible to get CD’s to repair?
Nooriginal setup CD's