^ Well there must be a reason why he installed Linux instead of Windows in the first place.
@cuteboypk: It might be an interesting experiment (though maybe not a very good business decision...) to encourage your customers to use Linux. But you might also want to consider the risks as people would probably not accept it willingly.
Long story short. Linux is an alternative to Windows, not a clone. If you absolutely must use Windows software, then you installed the wrong OS on your computers! Though I'd be interested in knowing what your thought process was when you decided to go with Linux?