Help needed urgently

I set up a new partition and when the mac restarted it said that it couldn't find a bootable device, so i thought to myself i'll go back onto mac and sort it out but i can't get onto leopard, it keeps booting into to windows and saying that it can't find a bootable device.

anyone know how i can get back onto leopard when i boot the mac, it keeps taking me to windows

thanks

Chris

Try holding alt when booting up and see if your leopard partition is there to boot from. If not put your install disks in reboot, hold c and run disk utility.

holding alt isn't doing anything, and i already have a dvd in the drive and i can't get it out

To eject a DVD on start-up, restart and hold down the main (left) mouse button

Ive done that but it doesn't seem to be working

Sorted this out now

thanks for everyone's help.