You were playing halo demo on the PC last night and someone with the name im a hacker entered your game and everyone else died everytime they respnded Why and did this mess up your computer?

Answer 1

They are probably cheating. Cheating is often called 'hacking' 'hacks' or 'hax', but this is not usually the case. They are simply using special programs or utilities, or have a modified game client, which can do things normal clients cannot.

It did not harm your computer.

It should be noted that using cheats and hacks in multiplayer games can cause punishment, such as losing your game account, cancellation of subscription services, or being reported to your ISP. Rarely, your ISP may choose to cancel your internet service, if you are causing significant harm to the game or business.