How to Install the latest Ubuntu in partition

Hello Techies!
I wanted to get a step-by-step instruction on how I can possibly install Ubuntu on a partition I made.
I am using a Lenovo 7757.
I have Windows XP32 on my C: Drive and I wanted Ubuntu to be on the D: Drive (the partition).
I am using an external hard disk for the boot to install it and have tried both the pendrive and unetbootin.
However, when I have tried to boot from the external hard disk, I received "boot error" and cannot leave the black screen.
I do not know how to fix this, has anyone encountered the same trouble before?
Hope you can help me.
Thank you.
