How Do I Properly Set Up A Dual Boot For Windows Xp And Ubuntu 11.04 On Two Separate Hard Disks

Now I want to use Ubuntu 11.04 on the 80 GB drive, so I have installed Ubuntu on it. There was not a single error at that time. However, when I restart, I don’t find any boot list and it directly opens Windows XP. I don’t find any mistake.

Can anyone tell me what I am missing? And what to do?

1. The GRUB is not correctly installed.

2. There are two separate boot loaders one one the 500 GB and a second on the 80 GB hard drsk and there is a problem between them.

3. Something else, which i don’t know.

Please help me find a solution for my problem.