how do i get registery keys back as ive lost some?

System Restore deletes any programs or setting that had been added to the computer since the date and time of the restore point and changes the setting back to how they were at that date.
You either need to reverse the Systen Restore (can be done within that actual program) or reload anything that you'd previously loaded and setting changed between the restore point and the date you resorted the computer from.

Stephen
March 2011