How to change the default start-up to windows?

I have installed ubuntu 8.04 recently.

after installing when i have to choose between wat operating system to choose it shows ubuntu as the default one and XP as d secondary. that is if i dont select XP it would by default log onto Ubuntu. I dont want that.

can that be changed? and if yes how?How to change the default start-up to windows?
A step by step guide:

https://help.ubuntu.com/community/GrubHo鈥?/a>