Check this links…
Download linux..
http://getintopc.com/softwares/operating-systems/linux-download-free-operating-systems/.

https://www.ubuntu.com/download/desktop.

Download poweriso…

http://www.poweriso.com/download.php.

http://www.tech-nich.tk/2017/05/how-to-create-bootable-linux-ubuntu-usb.html?m=1.

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