A few days ago, I installed Arch Linux alongside Windows 8 on a new Dell laptop. I did so by booting from a USB drive, and there were no problems with the install. I'm now trying to install CrunchBang alongside Arch and Windows, but I'm not able to boot from a USB drive. The option to boot from USB has disappeared from the BIOS, and I haven't been able to find any way to re-enable it. I've tried every option I can find, to no avail.
I've also looked into booting from the USB from GRUB, but I haven't had any success there; executing
ls from the GRUB command line with the USB drive connected just shows my hard drive's partitions.
I'm using EFI and GPT, and everything else seems to be working properly. Can anyone point me in the right direction? I'd be happy to provide any information that would help to diagnose the problem.