[BIOS] Issue to fix before installing OS X

Hey everyone, my friend and I have been stuck on this problem for a bit and after going through Google for awhile we are using this forum as a last resort. So here goes;

1. SAMSUNG 20X DVD±R DVD Burner Black SATA Model SH-S203B
   
2. XFX GeForce 8600 GT 512MB 128-bit GDDR2 PCI Express x16
   
3. Intel Core 2 Duo E4500 Allendale 2.2GHz LGA 775 65W Dual-Core Processor
   
4. Intel LGA 775 Intel P965 Express ATX Intel Motherboard
   
5. Seagate Barracuda 500GB SATA Hard Drive
   
6. CORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual
   Channel Kit Desktop Memory

We have a legit copy of Leopard to try and see if that could make my life easier.
The problem comes when we boot into BIOS and at first we had the error of "PXE-E61 - Make sure cables are connected". Then I went ahead and disabled "Boot from Network" through BIOS so that the computer can only boot from either the Harddrive or the CD/DVD drives and now the command line says; "Bootable Drive not Found - Insert Bootable Disk and Press Any Key." With the DVD inside and making sure that all the cables are attached we are at a lost at the moment.

If anyone can help out it'd be great.

try and make sure that all the drives are correctly recognized in BIOS. it sounds like the harddisk and dvd drive are not detected right...

I re-checked all the cables and I realized that it went over my head that the Leopard DVD isn't a bootable disc itself. Learning that I was able to get the Kalyway 10.5.2 DVD off Bittorrent and from there I was able to get everything going.

The situation now is that I can't boot into Leopard at all without having Kalyway in the DVD-Drive at the time of Boot. Also I have no sound whatsoever from my Intel Motherboard. Is anyone else having that issue?

My motherboard died, doing the Intel 965 Northbridge Chipset was completely unstable as I found out. I went ahead and invested on a $45 ECS 945 Chipset; which can only support 2GB of ram, but at least now I won't have to load the DVD everytime to get the Operating System working.

The only issue I have now is the audio. I went ahead and ordered an external USB port that should fix that deal. Thanks for the support.