If you have trouble starting Windows or the Registry files are corrupt, you can create a new Registry without having to reinstall Windows. Reboot your system to MS-DOS. On the command line type 'SETUP /pf' with the Windows CD inserted into the CD-Rom drive. This will replace the Registry with a new one replacing the SYSTEM.DAT and USER.DAT files. This should get your system going again, although you may need to reinstall some of your programs.