i used to have the "games minimizing to taskbar" issue way back when i had my windows xp single core system.
while the trigger could be multiple things (poorly coded game, background tasks or poor system specs) it looks like cod ghosts is a poorly coded game and that you arent the only one with an issue.
perhaps this fix for another cod title will fix the ghosts minimizing issue
https://www.youtube.com/watch?v=dI5LA_9znNo
if that isnt the issue and if you bought it on steam then perhaps that is the culprit and needs some settings tweaked.
if it was a windows issue or driver issue you would typically have more trouble than just with one game.
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you may want to specifically mention how it minimizes or when it does. the better you describe it the better we can tell what it might be.