W8 won't let me boot from my USB drive.

Hello; activate the MBR boot in the BIOS to have an MBR boot on the USB.

(from memory; saw another thread regarding Windows 7 instead of 8 = auto-source = Install W7 on a GPT partition | CommentCaMarche:
http://www.commentcamarche.net/forum/affich-26832191-installer-w7-sur-une-partition-gpt#11)

OR

you need a USB drive capable of handling UEFI boot = ubuntu uefi.

See here maybe:

[RESOLVED] booting from live USB 10.04 inoperative (Page 1) / Installing Ubuntu / Ubuntu forum:
http://forum.ubuntu-fr.org/viewtopic.php?id=1121121&p=1

"Ubuntu provides a special ISO for EFI machines with the secure boot of W8 called ubuntu-secure-remix; check here: http://doc.ubuntu-fr.org/ubuntu_secure_remix "

+

"ubuntu-secured-remix | Free software downloads at SourceForge.net : http://sourceforge.net/projects/ubuntu-secured/ "

Thank you for your quick response (oh, the wordplay!)
So actually, I had a first problem, which was that my Ubuntu installation was 32-bit and the machine was 64-bit. I then re-installed a 64-bit Ubuntu on the USB drive and this time, I am able to see the first interface after booting:

Try Ubuntu without installing
Install Ubuntu
OEM install
Check disc for defects

I tried each option, but every time I get a black screen afterwards and then nothing... So, if you have a solution for this problem...

Thank you

Hello; see this topic:

[Solved] USB 12.04.1 - Secure Remix 64 - UEFI - Black screen after Grub (Page 1) / Questions and information before installation / Forum Ubuntu-fr.org:
http://forum.ubuntu-fr.org/viewtopic.php?pid=10637571

"You have a display issue that is likely due to the fact that your PC is ultra-modern. Therefore, I think you should use the nomodeset option at startup of your liveUSB: http://doc.ubuntu-fr.org/kernel#modifier_les_parametres_du_noyau_pour_une_session-live
Since you have the Grub menu in black and white, you need to press the e key to manually add the nomodeset option just after "quiet splash": http://images.maketecheasier.com/2009/12/ubuntukarmic-edit-grub-entr.png
Then you will need to confirm by F10 I believe (it’s indicated at the bottom of the screen what needs to be done to validate).

Note that if this resolves the issue so you can boot from your liveUSB and perform the installation, don't be surprised if your installed Ubuntu doesn't work. The reason is that the "nomodeset" option was used by the live session but there are no instructions passed to the automatic installer to indicate that a necessary boot option is needed. The reason is that in many cases (but not necessarily yours), this option is only necessary on the first boot because it is often possible to install a proprietary driver that will handle the display and the nomodeset option will then be unnecessary. In short, you will have to do the same small manipulation (key e, etc...) to boot Ubuntu installed on the hard drive. At least for the first start...

Edit: if the nomodeset option is useless, try instead the option acpi=off"

Hello,

I would like to follow up on this post because I am in the same situation and the options nomodset and acpi=off do not make any difference.

If you have any other ideas...

Best regards,

John

Hello,
Thank you for the response. I had accidentally written in another post (I'm a bit of an idiot...). It turns out that the answer is to disable boot security in the security section of the BIOS.

Thanks anyway.

Best regards,

John