To close it, just select it in the list and click the End Task button. However you should not close any program in the Close Program dialog box unless it is marked not responding . The Start menu may come up, allowing you to exit more normally and give you a safe reboot. A decision was made to save a little by storing the year part of a date as two digits instead of four. No variability was allowed for the century that was to remain at 19.
Explanation Think of a digital clock.
In many, but not all, newer PCs this is exactly what occurs, and there is no problem - everything will be normal when the new century rings in. In many millions of computers there will be potential disaster. The potential for disastrous consequences is astronomical. All three need to be checked separately, though the first two will have greatest long-term significance for most users. First set the computer's clock to 2001, and reboot.