Well for this I will show you the Emergency Repair Disk (ERD) option for Microsoft Windows 2000. Follow the following steps.

1) Make sure CD-Rom is first Boot Device in your Bios

2) Insert your Windows 2000 CD

3) Once this is done boot up using CD-Rom Drive. ( When  "Hit any Key to Boot From CD-Rom" appears on screen, hit any key on keyboard to invoke CD-Rom boot) 

The following screen will eventually appear after Windows 2000 has load in device drivers. Press "R" to begin repair process.

Soon you will see the following menu. Select "F" to perform all repair options.

Now insert the ERD disk/s. 

This will repair the registry, system files, partition boot sector, and startup environment . Once complete then reboot your computer.