I have an old Pentium4 PC that I have rebuilt from spare parts and I am trying to install Debian on it so that I can use it as an homemade server.
Problem is, the motherboard (model P4S800-MX) won't boot from my USB 2.0 16GB drive formatted with FAT32 and prepared with unetbootin (from BIOS i set the boot device to USB ZIP first and then to USB FDD with no result, even after updating the BIOS to the latest version through floppy disk).

After losing a day, I thought if it would be possible to preload the Debian installer onto the hard disk from an another computer that has Windows on it or through an old Ubuntu LiveCD, but the guides I found only contemplate a drive that has already a bootloader on it or through partitioning.

All I want is to have the installer run and setup and download everything else from the internet like how the netinst image already does, is there a simple way to achieve that?
Burning the ISO to a CD-R is not an option, as I don't have an empty CD-R.