Swapping Gamertag without Xbox 360

I have 2 GamerTags - one assigned to me for my Windows 8 account, and one that I used to use when I owned a 360. I now only have computers and an Xbox One.

The issue is that I want to use my Gamertag (the old one) for all Xbox gaming - PC, Xbox One, etc. The only inforamtion I can find on changing it is using an Xbox 360, which I no longer have access to. Games for Windows - Live does not install on Windows
8.1.

There MUST be another way to do this - can someone please tell me how to go about doing this? I have access to both accounts, I just basically want to either merge the Gamertags, or get rid of the one associated with my Windows account.

Thanks in advance,

:)

 

Live Account over 360 and Xbox One

Has it been stated anywhere how it's going to work if you move to Xbox One & keep your 360 ?

Will you still be able to log into Live with your gamertag on both machines (ie swapping between the two systems at will) or will your gamertag be stuck on the Xbox One ??

 

GT on two consoles

Microsoft have said you can have your GT on the Xbox 360 and Xbox One at the same time without to need to keep swapping.

 

You can't merge them. I don't believe you can change the Microsoft Account on an XBone, though I could be wrong. There's a LOT of functionality that isn't enabled yet. If I'm right about that and you don't have a 360 then you can't do what you want. On
the other hand if you want to use the same account for everything you can just sign into your computer using the Microsoft Account attached to your Xbox account and you'll be fine.

windows.microsoft.com/.../create-user-account