How do I get my Xbox Live account ID?

To Techmod, im not trying to combine two gamertags really, just eliminate my currently unused gamertag that has a xbox live / windows live id / email address. The offline gamertag is my primary and i wish to make it my gamertag / widows id / email address.
The offline account with my achivments is the account i wish to have xbox live with. If i sign up with xbox live gold membership on my offline account, will this delete my other live account? How do i do this.

Each Live ID can only be associated with one gamertag.

What you can do is create a dummy Live ID, then switch the gamertag you want to get rid of to that ID. Now your primary Live ID can be used to sign up with a new gamertag. Here's how to do it:

support.xbox.com/.../manage-live-id.aspx

Click on the "Switch your gamertag to a different Windows Live ID" link.

I found this

"Before you can change the Windows Live ID associated with a child account, you must provide the Windows Live ID information for the adult account with parental control."

This is what is happening to me but i only have my account on the xbox no Parental one. So how do I chang my account to act as the parent?

You can find out how to do it on this page under "Switch your gamertag to a different Windows Live ID." support.xbox.com/.../manage-live-id.

No that changes my whole windows live ID account, My live id account is mine not my sons...I dont want to change my windows live id...I wanted to unattach it from my sons Xbox live gamer tag not change my windows live id all together...i just found a way
and changed his gamer tag (i just took his and made it mine changing it to what i wanted) and made it mine underthe gamertag name that I chose and not his...I had to figure out how to do that with out having an xbox console....which was a task as it is not
listed on line anywhee and microsoft xbox live help could not tell me how to either....but I was able to get it done, thank the Lord!..

yea, if I would change it your way it will take my windows live id give me a new one and then my original would be gone forever and it would have still been linked to his account, I just had to hijack his acount and make it mine...so he will have to get
a new if he ever gets another xbox live console...thanks for the sugestion, even though it would not have fixed my problem.