In the beginning I can't seem to open briefcase and then I have trouble..

Which briefcase? IF it's the briefcase that you get out of the fire near the fallen helicopter, then just go to your inventory and examine/check it. As you are looking at it while examining it, flip it where you see the handle. There is a button there you can push where it can open. If it's the one you get out of the locked cabnet thing, then you need to find a lockpick for it.

What kind of trouble are you having with the duplication machine? Try to be alittle more specific. Like what have you done so far with it and what have you obtained(item wise).

I hope this helped some, =)

Okay.... If it's the briefcase you get from the fire, go to inventory, check it and push the button. If it's one to be opened with a simple lock, then you need to find the hemostatic medicine,give it to the guy who let you out of your jail cell and he'll give you the lockpick. For the duplication machine, you have to go to the machine with the little window and open it. The eagle is in the draw near the computer where you talk to Steve in the same place when he asks Claire about her brother. After you put the eagle medal or medallion into the machine, you'll need to get the briefcase that's in the fire. Read what I put for how to open it and you'll get the special alloy. You don't have to worry about the metal detector, as it can't detect the alloy. Go back to the machine that looks like it has a metal pencil and place the alloy there. It'll make an exact replica of the metal and you can put it in to the double gates. Hope this all helps.