Booting problem (Bootcamp)

I used bootcamp to keep a Windows partition on my macbook pro (Leopard). However, it kept hanging with Windows so I decided to remove the partition. But, after all this, when I restart my mac, it searches for a Windows boot and gives errors. I can avoid this by using the Alt key however it's annoying.

So, how can remove this useless boot sequence?

On startup chime press Alt key and it will bring up the boot menu. Boot into leopard and goto System Pref > Startup Disk. In that change the startup disk to Leopard