Start with the mission-critical systems. You'll probably find you haven't got time for the rest. Increase your fire-fighters. It's the programs that don't. Expect your Y2K effort to end in about 2002-2003.
Manual inspection is the only answer.
Silver Bullets are good for vampires. Please visit Elmbronze at IBM Mainframe and Telework . You may read that you should set your PC clock to a few minutes before midnight of the 31st December 1999, and leave it running to see what happens when the year changes. To get yourself out of the resulting guddle will be very difficult. Yes - Link to rightime for a PC patch .