if some one is install windows from unregistered software source then it is not genuine software having no registered certificate but still computer runs the window. it does not provide the security to the system, is it wise to install such softwares?
There is a difference between unregistered software and software that does not have or is not eligible for a valid license. In the US (where I am writing from), registration is not required to have a warranty on items purchased, though some software vendors would require registration to access program updates. Unlicensed / pirate software is never legal here.