Wow, that sounds like a pretty impressive computer. Most ram I've heard of is 4 gigs. But anyway, in your original post didn't you say you played against one of the 1700 or 1800 level personalities? Not the actual 'chessmaster' personality whose rating is ~2900 according to the game?
The other personalities are handicapped versions of the chessmaster engine to simulate players at that level. I'm gonna go ahead and say its not remotely possible to beat the chessmaster engine in 13 moves.
It's the ELO system. You beat higher rated enemies and lose against lower rated. The low rated ones should have had a lower rating to put you back down to 1200.