Halo: Combat Evolved

Hi all,
I need some help understanding how to use the many various patches for the game Halo: Combat Evolved. I downloaded the game from the Micro$oft Web site, tried a few of the patches but none seem to work. Perhaps the patches don’t work with the Micro$oft’s games. Also I found some serials for this game, but there seem to be nowhere in the game to use these serials.

Is there anywhere else I could download this game and try the serials or a patch for it?
Also which patch? Way too many v.

Thanks in advance for your help

No warez talk here, please keep talk of warez on other websites.

hold on fycus, it seems the boy downloaded the game from microsoft's site.

is there a filter for microsoft that automatically puts a dollar sign there or do people actually have enough time put it there?

not to jump the gun, but I decided to google Halo: Combat evolved demo into google and came to the Microsoft site before you posted mikeeegeee. I saw that the only downloadable thing Microsoft had was a trial, and the trial does not need a serial to be entered. If the guy mentioned serials, he was obviously referring to the full licensed game, which is warez. Thank you, come again.