First of all you need to be on the most recent dashboard which is 16537. Use Google to find out how to upgrade. I used Flash360 to generate a NAND file. Got my CPU key by booting into Xelllaunch. Then I used Horizon to generate a new NAND file with the 16357 dash and my CPU key combined. After that Flash360 again to put the NAND on my XBOX.
Now for Call of Duty: Ghosts:
You probably already downloaded the two iso images of Ghosts. Next use exiso to extract them. Get it from this location: http://digiex.net/attachments/downloads/download-center-2-0/xbox-360-content/apps-pc/7467d1318226690-exiso-download-extracts-xgd3-images-exiso.zip
When extracted you now have to directories. Copy the first directory (eg. ghostsdisc1) to your games directory: hdd1:\\games
Now browse to the directory in which the second iso was extracted. Open the content directory and then the 0000000000 directory. You’ll see another dir in there with a code 415608FC. Copy this directory (CRTL-C)
Browse to hdd1:\\Content\00000000000 and paste the previously copied directory in there. After the copying has finished you a ready to go! Enjoy