What to do if Half-Life the game on PC asks for a cd key (Cracked)

In this video I show you what to do when Half Life on PC asks for a serial key. I have found a crack in it and now I have shared it with the world. My name is Shaun Roselt and in this video I was age 13. I came across this nice trick when one day I got the game from a friend, but I did not have the serial. I then just held the A letter and by my big surprise it worked and the serial was accepted.