Ok, im trying to install Leopard via flashdrive or CD. I have it burned to CD, and formatted to the flashdrive. But for some reason it won't boot from it, it has a blinking underscore for a couple of seconds then goes to booting windows. It happens with both iATKOS V7 and Kalyway, what do i do?

BTW I used transmac for burning to cd and flashdrive.
Specs:
BFG NVIDIA 9800GT 1GB VRAM, factory overclocked.
6GB Kingston Hyper Memory RAM
Western Digital 640GB HDD
AMD Phenom II X4 945 Quad Core @ 3.0 GHZ
Asus M4A78-E Motherboard
Windows Vista Ultimate