(initramfs) Can't install Ubuntu! I tried on several PCs with different distros!

I'm totally new to Linux :)
so please forgive my lake of knowledge!

Okay, #1- First I tried to install Linux Mint -which is Ubuntu based distro!- on an old "IBM S50 ThinkCenter" desktop!
& I managed to burn a CD after failing to boot from a live USB to find only the same message again & again (1962: No operating system found. Press F1 to repeat boot sequence.)- after many tries I gave the cd a shot but this time surprisingly the Mint logo shows-up :) but my Pc doesn't like happy endings! so after I open the "Install linux" icon & choose "English" as a language the "Preparing to install Linux" screen freezes! So I gave up on that PC.

#2- Now I want to install Linux on my laptop -"Toshiba L650"- this time I try another Ubuntu based distro "Elementary OS" to find a new error this time!: after the glowing loading logo of the Elementary splash a black screen showed-up saying:

[ 0.317932] platform wdat_wdt: failed to claim resource 4
[ 0.317993] ACPI: watchdog: Device creation failed: -16

BusyBox v1.22.1 (Ubuntu 1:1.22.0-15ubuntu1) built-in shell (ash)
Enter 'help' for a list of built-in commands.

(initramfs) Unable to find a medium containing a live file system
_

So, I'm determined to install Linux & learn command line too within a month!
Any suggestions or info would be greatly appreciated :)
Have an awesome day :)