Newbee has a question

I would like to try to post a story but have a really basic question:
What program should I use to write/compose it? Is any format better or easier than others: Word, Notepad, Other? I've read the FAQS and posting seems complicated, but first I have to compose, rewrite and edit the story. I use XP & Win7 and would be willing to download or buy a program if there was a real advantage.

I'm so new to this that I don't even know what I don't know! Pretty dumb huh? Any help or suggestions would be warmly appreciated. I throw myself on the group's mercy.

Hugs,

Maren Sorenson