Restore Windows XP boot from Dual Boot with Ubuntu

Hi,
I’ve been using dual boot on my laptop for a sometimes, Windows XP and Ubuntu 10.
The default operating system is Windows XP, so Ubuntu was installed as a second operating system.
The booting screen currently is handled by Ubuntu.
So every time I want to log on to my Windows XP, I need to choice from the screen boot loader.
Now I want to make the default loading to Windows XP again, and get rid my Ubuntu.
But how can I do that?
I’m not mastering Ubuntu or an expert in Windows XP. Please help, it’s been annoying for me.
Thanks.
