Topic, Strange messages come up on my x-box! (MW2 ONLY!)

  Yearh. As said, hackers can infiltrate your XBox without the need to do more than play with you. Contact Microsoft.

  I dont hack! i was going online surfing thru barebones when BANG! i stabbed someone and got like 20billion exp!
After that the message started appearing.

  Contact Microsoft. XBox is an easy hacker-goal, especially if you've been doing online surfing, downloading/running external software (Hacks, etc.. Not judging you here)

In the future, keep away from running external software, browsing or any other online action (Not including games).

  I stand by my first analysis :P

  Virus perhaps?

  Looking at url and the bit in parentheses, I think it's pretty plain what the problem is.
:P

And I agree with Marc (at least the first part)
:P

  dude you just got owned o.O
idk...but I will give you the best advice I can:
ask JP XD

  OK this is the message that comes up: (gamer tag)INFECTED BY SHARK ON WWW.HACKCOD.FR Team HCD|Gutu<3 Can anyone tell me how i can stop this from happening. (BTW when this happens there is always someone with the clan tag {@@})
It happens frequently and is anoying when it flashes up on the screen. URGENT HELP NEEDED!!!!!!!!!!!!!!!!!!!!!!