If I give notice of leaving a job...

State: COLORADO

If I give 2 month notice of quitting my job in Colorado, could I still be fired or forced to leave if I still perform the duties my job requires?

Yes.

This question has been answered over and over; I think this is the third time this week and it's only Thursday.

In ANY state, your employer has the right to accept your resignation with immediate effect unless you have a contract or CBA that says otherwise. In your specific case, they can let you go at any time they choose during the two months. And no, they do not need to pay you for the notice period.