41 ( +1 | -1 ) ok,here goesthe opening is kinda lack for black.i dont know if you are playing some kind of hypermodern system or just didnt the basic so i dont go in there,but white have some initiative.i think you didnt see your knight at a6 get batteried by the bishop at c4 and the queen at e2,so you lose a piece there.plus after the exchange at d5,white win another piece at d5 .so basiclly i think you just lack in vision.
42 ( +1 | -1 ) Your problems......started in the opening.3...Nc6 was a mistake,as you blocked the Bb7 on the long diagonal. This N usually goes to d7 ,where it supports a break at either c5 or e5.Then you lost several tempi with the same N,and then hanging it,and then another piece was just icing on the cake. Whites Q sac was nice and sound,as your K was buried by the 4 White pieces.Your Q and R were totally out of the picture,and could do nothing to stop the mate.
40 ( +1 | -1 ) white_disc, you are not permitted to seek advice or assistance regarding any game currently in progress (the second game snippet you posted). Even though you aren't asking about what you should do about the current position necessarily, any advice or analysis offered about previous moves in your game might benefit you in some way, which would be unfair to your opponent.
9 ( +1 | -1 ) I think.....you screwed up beacause you weren't careful enough. Watch out for your pieces and you'll do fine.
91 ( +1 | -1 ) My 2 cents worth3... Nc6 is not a "book" move but I have to disagree with myway316 , I don't think it is a "bad" move, although 3... e6 was to be preferred. WGM Chiburdanidze won a game with playing the Knight to c6, as so has IM Csom. However, yes, myway316 is correct in saying that the Knight usually goes to d7. I just dont think the move is a blunder, that's all.
Instead of 8... Nf6, maybe 8... Bd6 9.o-o Ne7 would have been a better defensive piece placement.
10... o-o is a grave blunder. 10... Nb8 followed by 11... Kf8 was neccessary. However, if one insist on castling... even at the cost of a piece... then 11... Bxa6 followed by 12... c5 would allow (some) counterplay.
However, I think the troubles started back with 5... Nb4. 5... Nb4 isn't a tactical blunder (it loses no material) but I think it is a positional blunder (gives Black a bad position). 5... Nce7 6.Bc4 Nf6 7.o-o c6 8.Bg5 seems much better.