Log into your BIOS and ensure that booting from a USB device is enabled (I think the x58 has that feature).  If I am wrong, I am sure someone will correct me.

Make sure the USB is plugged into your machine and go into your BIOS - Go into select the order of the drives booting and make sure the USB is first in the list, should work.

What bootable device are you attempting to use?

Got it. Thanks

just as a future fyi: when i used my usb thumb drive to install win7, i went through the steps found online on how to make the usb drive bootable (using cmd.exe), but what that does is to make it look like a HDD and not a removable drive. when starting the machine, the usb drive was inserted and i hit the ESC key to go into the boot menu and i selected it. i didn't bother changing boot order or devices in the BIOS.

onosan

Hi WyattT
I know this is an old thread, but did you solve your problem? Have the exact same problem on my 758 running 78-bios:
- first boot device set to Removable
- usb-stick doesn't show up in "bios harddisk boot priority"
- bootable usb-stick tried in diff ports
- returns nothing but "no bootable device found"

 
You answered your own question:
 
If the USB stick as you call it doesn't show up in the Hard Disk Boot Priority menu in
BIOS, then the USB stick as you call it is not bootable, is not recognized by the system
so that you can select it.
 
How did you make the USB stick bootable? Tell me what you did and I'll tell you what
you did wrong, ok, fair enough?
 
rexrzer77 

onosan

Like in Wyatt's case my USB stick boots instantly on other pc's .

BTW it is made with a version 5.5 bash script from Digital_Dremer on Insanelymac.com

 
I went to the site you cued up here and couldn't find anything like you mentioned
called "Digital_Dremer", at the Mac installer web site. Sorry, but maybe I just don't know
how to *search* there well, it's a pretty confusing site for PC people who used to be
Mac people....
 
You say that this USB stick works on other PC's? Maybe it doesn't work on this particular
motherboard because your boot loader is for Mac USB installs? I wish I could have found 
what you referred to then I could comment further...but basically...
 
You need to make a new USB Stick with one of the normally acceptable methods for making the USB stick bootable, which all you have to do is use Google to find: Google is your friend here, not the Mac site.
 
Good luck, and I hope this helped.
 
rexrzer77 

This thread is old but when i googled the problem this thread came up so i figured might as well continue here instead of making another thread.
 
Anyway, i have the same problem. I'm using UltraIso to make the bootable flash drive using the 4 write method. USB-HDD+, USB-HDD, USB-ZIP, USB-ZIP+ and none of these mode allow the Classified 3 MB to detect the drive to boot.
 
The odd thing is when i tried it on other pc, they boot just fine. So i figured it might be incompatibility w/ the drive. I was using the Corsair Xporter usb drive so i switched to my other usb boot drive, which is a Sandisk Cruzer.
 
I tried all 4 mode again and it's still not detecting it.
Then i decided to try YUMI - Multiboot USB Creator (which works in the past for me as well and still does on other pc)
 
site: http://www.pendrivelinux....multiboot-usb-creator/
 
I also tried to disabled USB Mass Storage in BIOS but disabled or enabled seems to make no difference either. Also, the drive isn't seen on bios either. So I'm not really sure what's going on here.
 
Please any help would be appreciated. Thanks!
 
Btw. I'm trying to write a Window ISO onto it, and i know it works, b/c i've used this ISO before to install it on other PC.

I saw this old thread on Google .
Why did no one suspect that Tt was wrong? If Bios setting was correct , 
Why did no one ask the OP, how he got bootable USB ?