Hi. I have been having a problem with my wife's computer. She doesn't like windows 8 and wants windows 7, no problem. Only the machine (HP 19 all in one) refused to ever boot into/for legacy devices (ie- windows 7 usb bootable drive). So, I decided to format the hdd, but ONLY Linux Mint would boot. Not Kali, BT, U/Kubuntu, or even Knoppix(even after Linux Mint installation). However, when I did install Linux Mint, the machine would not find a bootable drive(mount). So I attempted it again manually, and still will not boot up. My question is, do you have any idea why Linux Mint is the only Linux distro that will boot up live?
I've tried usb and dvd's before you ask.
Thanks
Matt
I used usb pen loaded, windows 7 usb/dvd downloaded, and rufus.

It's the UEFI. You've got to go into the BIOS settings and change it from "Secure Boot" or UEFI mode to BIOS or Legacy mode.

Some Linuces work automagically with Secure Boot and/or UEFI (not the same thing): most do UEFI these days though not all. Few automatically do Secure Boot. Windows 7 can be forced to do UEFI, not Secure Boot.

Ubuntu may not boot up because grub may need updated. Does Ubuntu show in the Grub Menu?
To solve that; while your booted into Linux Mint run this cmd as root:
I don't know why Mint is the only distro that will boot on that HP.
Some installers don't have the option to try the distro first and place you right into a fresh install.

Is your HP a UEFI machine?
Is secure boot disabled?

I've had similar issue's myself.
My Sony Vaio will only boot Centos, Fedora or Debian.
For some reason I have not be able to get any other distribution to boot.
Another thing; it could also be that the machine only recognizes 3.0 usb's and not 2.0's.

-::-I suspect it could be something proprietary or perhaps a UEFI issue.-::-

Is this your wife's machine?
http://support.hp.com/us-en/document/c04094869

I'm not an expert with the UEFI EFI partitioning.