Activision Call of Duty: Black Ops "zombies game online" Questions

zombies online and it works just fine. My console does not crash with any other games, single or multiplayer. Again, this happens ONLY on multiplayer Call of duty: Black ops. I have switched my router

zombies on black ops on the xbox the levels register, but when i play zombie maps five, ascension and nacht der untoten the levels do not register when i die can you help me solve this problem please?

...game types or at all online. it keeps saying lost connection to or must be signed into xbox live acount. you need an xbox live account, a connected modem to your xbox, and to sign in in order to play ...