cant install leopard 10.5.1

[cmiaoqin]

my specs

when i insert the leopard dvd,

it keep searching for root device.. hw can i tell the computer to use my 500gb HD?

1. amd athlon 64 x 2 3800 + processor
2. asus a8n-E s939 NF4ultra pci-e glan
3. patriot 2gb ram - ddr
4. i got 250 gb hitachi HD for pc (winxp-ntfs) and i just brought a 500 gb WD HD (only initialize, not yet format) to make it into mac
5. xfx geforce 7900gt 256mb pci-e graphics
6. antec 480 watts truepower 2.0 supply unit
7. benQ dvd writer
8. linksys G wireless adapter