HELP PLEASE - reboot and select a boot device

So I helped my friend put together his new computer but i noticed he never bought a new hard drive or optical drive so we had to use his old products which were both IDE. He only has 1 slot for IDE on his motherboard and we connect that with the other 2 ends to hard drive and optical drive. We boot up the computer and it asks him yo please select a boot device and restart. We restart and i go into bios and change the priorities but we still have the same error message come up. the hard drive was working fine on his other computer so I'm honestly out of ideas as to what the problem could be. any help would be greatly appreciated.

also -- I've never set jumpers before in my life so we neglected to do so. does this need to be done if i'm connecting 1 hdd and 1 optical drive on the same ide cable ? if so can anyone explain to me how to do this. thanks

I connected the blue ide connector to the mobo, black to the hard drive, and gray to the optical drive

Most newer motherboards have multiple disk controllers. Each controller can be enabled and configured in the BIOS. Make sure the ATA-133 (may be a lower number depending on the motherboard) controller is enabled in the BIOS.

Also, newer motherboards (boards supporting socket 775 processors or newer) don't require jumpers to be set on the hard drive. I would remove the jumper cap from the drive. This will set the mode to cable select. Then try it.

Usually you'd setup and enable/disable the disk controllers under 'Integrated Peripherals'.

What kind of motherboard is it?

This is supposed to be a new build. Trying to figure out what kind of new motherboard would have an ATA controller that wouldn't allow 'cable select' (no jumpers capped) otherwise I would have pointed him in a similar direction?