Since you say "the opticals" (plural) and "the hard drive" (singular), it sounds like you had both IDE ports in your old machine in use for at least three IDE devices. I suggest you set up the new machine with your old HDD as the Master unit on its only IDE port / cable (plug the black END connector of the cable into the HDD and set its jumpers to Master), and ONE of your old IDE opticals as the Slave device on the cable. Leave the other optical unused for now.
Ideally you need to do what is called a "Repair Install" when you move an HDD containing an OS to a new machine with a whole bunch of different devices. The best way to do this is with your original Win Install CD, but you don't have one. You still should be able to do it if you can borrow an Install CD for the SAME version of Windows. For example, if your HDD has Win XP Pro with Service Pack 3, try to borrow an Install disk for that same version.
You configure your BIOS Setup so that the machine will boot first from the optical drive, and then from the HDD. You place the Install CD in the optical and boot from it just as if you were going to Install Windows. BUT do NOT do a normal Install. Instead, watch at the beginning for options and choose a Repair Install. This process will survey the hardware devices found in the machine and compare that to the drivers already installed on the HDD, then go about fixing all the mismatches. When it is done you reboot after removing the CD, and it should work.
So, how do you get the second optical unit into play? Three choices.
1. Scrap it and buy a replacement that has a SATA interface.
2. Buy an IDE controller card you can plug into a PCIe slot, and hook up to that.
3. Buy an adapter that allows you to plug an IDE device into a SATA port. (Be careful not to get the reverse unit that plugs a SATA device into an IDE port.) Read up carefully in its instructions how you must set the jumpers of the IDE optical unit (Master or Slave) to use the adapter.