A screen comes up on my tv

It sounds like in this case there are parental settings that are enabled on your xbox that are preventing you from signing on to live. Here is a post from an online forum that should fix your problem.

Re: Way to Override Parental Control on Xbox? Quote: Originally Posted by Kabuki Parental Control Override Code:
Go to Settings
Highlight Parental Control
When the screen pops up that says Enter Pass Code press: X, Y, Left Trigger, X
You'll be taken to the parental controls screen where you can disable the password previously entered -

1. Log in to myAT&T.
2. From the myAT&T tab at the top of the page, hover over the Wireless link and select Phone/Device under the My Wireless Service heading.
3. From the My Phone/Device screen, select the Unblock SIM Card link under the My Make & Model heading.
4. The Unblock SIM screen will display your PUK code and will give you instructions for unblocking your SIM Card.
   

Once you receive your PUK code, you will need to enter it into your phone to set a new PIN code.

Default code is "0000" on most sharps to enter the V-chip settings. If not you will have to reset the password which is listed in the manual if you have it.
Clearing the password or secert number on newer sharps are as follows.
1. Press MENU to display the MENU screen, and then arrow to "SETUP"
2 . Then select on of the options until the password or secert number input screen dislpays.
3. Press and hold both the "Channel Up" and the "Volume Up" buttons simultaneously until message apperas on the screen. Then you can enter new or leave blank number.

If this doesn't work goto sharps web site and download the manual if available.

To reset password go to MENU
Go to VCHIP SET and press enter
Enter the code you want to set and press enter.
Press RESET button
Reenter the same code again and press ENTER
Enter the same password again and this should let you in to the settings

Good Luck....

first go to configure terminal mode...thn type enable secret space ur password thn it willl b secure

Hope that they didn't actually reset it and enter 1234. If this doesn't work, you'll have to play the "numbers game" and try all combinations...accordianman