How can I link my Xbox Live gamer tag to my Hotmail account?

I already have an Xbox live account and I plan on getting a hard drive for it soon (I'm using a Memory Unit) and I would like to download things straight from my computer to the Xbox. I went to the Xbox Live website and tried to link it but it kept asking to make a new account, although I have one. Help anyone?How can I link my Xbox Live gamer tag to my Hotmail account?No clue.