Cant get on computer to install my norton

Hi ALL, i want to install my norton on my second computer but when i turn the computer on, it is stuck on the DOS screen that gives you the options to 'start windows normally', 'start in safe mode', etc... Which ever one i choose does not result in the launch of windows, it says that the windows could not start because "the following file is corrupt or missing" \windows\system32\config\system..... It says to try & repair by the file by starting windows setup using the original set-up cd rom & selecting "r"..... I do not have the disk. WHAT can i do?? I do not want to lose my documents or baby pics which are on the hard drive! Can someone please give me some options to try?? ID REALLY APPRICIATE IT BOYS! :)