how do i switch custom kernels?

Question

hello guys,

i have created and installed a new kernel in my ubuntu system, but now i have added a new system call and created a new kernel, how do i set this new kernel as the one the OS should boot from.

dpkg -i kernel-image-2.6.deb

i tried this on my first kernel and this set the kernel to this one

then i added a new system call compiled the new kernel and called

dpkg -i kernel-image-2.6.Custom.deb

but now when i reboot it stays as the older kernel,

any ideas on how to switch kernels?????

thank you