Can Software be defect free?

From QThreads.com:

This topic could have been discussed 'n' number of times. But when it comes to software automatically discussion leads to defects in software and damaged caused by them. Business, people, organizations get affected because of buggy software.

Every day we read about new methodologies, new tools, and new approaches about how software can be made defect free? Still it's a same story everywhere. This January, Microsoft released as security update for WMF vulnerability. But this is just not the case with any particular software application. Defects are everywhere and 10-20 years down the line usage of computers is going to increase tremendously. Software is going to be used in almost each and every part of our daily life. So if defects occur at such a frequency in a software application then really, it will be a chaotic situation.

So what do you think how a software can be made defect free?