Pretty simple do the following steps:
Download tinker:
http://games.softpedia.com/progDownload/Tinker-Download-55437.html (regular DL link is corrupt on xbox.com)
Download Games For Windows Live:
http://www.xbox.com/en-US/live/pc/downloadclient
Download missing dll to run tinker, extract to installation directory of tinker:
http://www.dll-files.com/dllindex/dll-files.shtml?d3dx9_41
1. Launch tinker, recover a unbanned account on it.
2. Sign into xbox live, it will prompt you for an update, say yes
2a: (this step is only needed SOMETIMES, try step 2 first) If you get a prompt asking for a serial number, go here and follow this method for a kane and lynch serial, this will work with tinker, use serial on BANNED account:
http://versatile1.wordpress.com/2011/07/01/get-a-free-games-for-windows-live-key-thank-you-poland/
3. After update is complete, recover banned account, and it will obviously say its banned.
4. Sign out of it, then sign back in, however, as soon as you see "Signing In" repeadetly press the "Home" button on your keyboard.
5. This will do the sign in glitch. Now press the home button again, click on your profile and then edit profile
can edit everything but gamertag.
Enjoy guys!