I couldn't get the PGN, so I can't put the games here, so here are the links:

http://www.chess.com/echess/game.html?id=1276501 http://www.chess.com/echess/game.html?id=903411

 

To get PGN (when you're in the games page), tick the box at the right corner and click Download PGN button.  Use that text in creating a chess diagram.

Now I took the liberty of putting the diagram for the first game only, with my annotations.  I guess the main factor is carelessness...  It's good that you posted your game where you lost--you learn more when you lose. 

In the game verse Mackattack all you had to pay was 33....Nc5 and even the game up. Mack can't push the pawn because you take the queen and guard the rook.

Oh.. Oh well.  But the game against CLOPINET was really humiliating. (The end)

I think a critical mistake may have been 9. ... Qxd6. Your pawn chain points to the queenside, so that's probably where you should play and this move does nothing to increase your queenside pressure. The correct move in my opinion was 9. ... cxd6. The reasons for this are:

1. Increases control of the central c5 and e5 squares hindering white's mobility.
2. Allows Qa5, Rc8, and Nc6-a5-c4 pressuring white's weak a3 and c3 pawns.

I think the game might have continued:

9. ... cxd6 10. c4 dxc4 11. Bxc4 d5 12. Bd3 Qa5+

Then 13. Qd2 leads to 13. ... Qxd2+ 14. Kxd2 Na5 15. Ne5 Rc8 with pressure on the c4 and c3 squares, an open c-file, and not much happening for white. 13. Nd2 is even better I think because 13. ... Qc3 is filled with threats and can be followed by Na5 and Rc8 with a lot of pressure on white's position. Note that if 10. c4 is not played and white casually develops the bishop, 10. ... Na5 followed by 11. ... Rc8 stops hopes of c4 forever.

I could be wrong about some of this, but I think in general black can gain a solid advantage by creating a lot of queenside pressure here. Comments anyone?

Why did you castle queenside into his open b-file???