Fedora has a really nice way of installing on a pen drive, real simple: https...

Fedora has a really nice way of installing on a pen drive, real simple: https://fedorahosted.org/liveusb-creator/ and will allow you to use any .iso image to create your pen drive install.

Ubuntu has a few similar apps as well.

You may want to check your laptop bios to make sure it is booting to USB, and not CD or HDD

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