OK. Let's start this over.
Your motherboard has 2 IDE connectors (Primary 0 and Secondary 1). So you can connect 4 IDE devices. HDs are usually connected to the Primary IDE channel. On both channels you can connect 2 drives. One has to be the "master" and the other the "slave". You can change this with jumpers in the back of your HD.
IF you connected your drive to the first cable that also connects your HD, you have to set your NEC as slave (to do this put the jumper in the back of the NEC in right place).
IF you connected your NEC on the second cable and it is the only drive on this cable you have to set the NEC as master. If there is already HD or a CD-ROM, etc. connected, make sure one is master and the other one is slave. If your computer still doesn't recognize your NEC, switch.
Don't forget to check weather you connected the power cable to the NEC.
To go into BIOS turn the computer on and press [Del] for a couple of seconds. (Usually it's Delede, but if not... there's always a message telling you how to go into BIOS).
The Bios starting screen should display your Harddrives and your Optical Drives.
Well... that's the best I can do now, since you don't give any more specs about your system...