Looking Best Chess Game?

Yo this is my first time to write this.

I'm big fan of PC  game chessgame.

Does anyone know what best tittle chess game for PC platform? I'm Looking the best chessgame for PC which has a great Difficulty To Beat? (Grand Master Difficulty) and Hard to Beat.

Pleaz Help Me . I want To play it very soon

I'm Desperate looking for the best chess game for this PC game.

sorry about the spelling in english.

trying my best to write in english.

Playing against the Chessmaster on Chessmasters are impossible XD, but its a great chess software.Meu2k7

Yep 

that chess game that comes with windows vista

What about Battle Chess? Do they still make that? I don't know how good the AI was, but you can't beat how the pieces take each other out. LOL. :D

If you want a real good expereince, I'd suggest playing chess online on some of the sites that offer it free. E.g. Yahoo games etc. You just can't beat the enjoyment, imho, of playing against other real people. They may not be as good as grand master level computer, but some of the stuff they come with as far as strategies go is just cool and fun. Same goes for any strategy game actually, online against other people is just so much fun.