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.
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