Hi Lothar,
You typing looks Spanish but your callsign German, I wonder which is the correct guess. German I can, Spanish not. I will try to give the answer in English:
Your PC should run CoD fine.
1.) run CoD and go to the Video settings and set it up to run in WINDOW MODE
Select the mode it offers you first. It will probably be very small (640x480)
Then start flying
Press alt-TAB to go to the Win7 desktop
With the mouse pick a corner of the CoD window, press and hold the right mouse-button and extend the CoD window to the appropriate size for your monitor
Release the mouse-button
Click somwhere inside the CoD window in order to go back to the game
I hope the flying is satisfactory.
Stop flying, exit the CoD (finish the game).
2.) restart CoD and go to the Video settings and set it up according to the screen below
EXCEPT THE WINDOW RESOLUTION (the 3072x945 is for MY MONITOR, yours is different)
Fly again and now it should be running fine.
I do not know how good your PC skills are. The next step may be complex for people with no PC skills:
3.) setup SLI
go there and look how it is done in the first page
http://forum.1cpublishing.eu/showthread.php?t=23199
I hope it helps.
~S~