Unable to boot a IDE hard drive connected with an ide to usb cable

Ditto what Hawkeye22 just wrote:

Check the "Boot Priority" in your BIOS:

chances are good that your BIOS will not allow your computer
to boot from a USB device.


Your BIOS may also have a category for "hard drives":
if a HDD does not appear in that list, then
it's almost a sure thing that your computer cannot boot from it.


Also, as a general rule, you can expect the least amount of trouble
if you cable an IDE/PATA HDD to the "Master" position on the ribbon cable:
that's the connector at the very end of the cable (usually black in color).

Also, you should force "Master" mode by adding the required jumper
on the IDE HDD. This will eliminate any possibility of a chipset and/or
HDD that does not operate in "cable select" mode.


The middle connector works best in "Slave" mode.


There is a color code convention for Ultra-DMA ribbon cables:

blue => motherboard
black => master
grey => slave


(If you know what you are doing, you can switch the jumpers on both HDDs
and then black => slave and grey => master.)


HOWEVER, never EVER connect a single IDE/PATA HDD to the middle connector
with nothing connected to the black/end connector:
that will cause signaling problems with the dangling end of the ribbon cable.


Hope this helps.


MRFS

If the IDE to usb cable doesn't present itself as a mass storage device then I don't think you can boot from it.