You get the keys to Fort Constantine during a quest for a man in Underworld named Mister Crowley. You either have the choice of giving the keys to him or once you get the keys from the people instead of giving them to Mister Crowley you can use them to unlock the doors yourself. Once you give away the keys to Mister Crowley it is impossible to get into Fort Constantine.
There is no more a master key in Fallout 3.
yes
If you are refering to the key to the double doors beyond M.A.R.Go.T. you can just talk to her after getting the senate id, or a skill check. If you are talking about the key to the capital waste land, you get that after getting the fuse. The fuse is on the main sentry robot.
contract killer perk
You have to find the password to the terminal left behind by the Keller family. There is a great guide on gamefaqs that describes the process in detail. http://www.gamefaqs.com/ps3/939932-fallout-3/faqs/55585
You do not need a key to open the vault. All you need to do is go to the blinking box next to the door and it will say to press a button to activate it. When you press the button then you will hear a siren and it will open the door.
there is no key it opens at the end of the game ps. there is no benefit getting in there... its just a room
After a bit of searching in many of the metro's compartments, you will run into M.A.R.G.R.E.T. Engage into conversation with her and steer the conversation into her powering the presidential monorail. You can now use it freely!
Occasionally Fallout: New Vegas will freeze, but not as frequently as Fallout 3.
fallout 3 psp??????
There is no such place in fallout 3.
Fallout 3, Fallout 3: Game of The Year Edition, Fallout 3: Broken Steel/Operation Anchorage/Mothership Zeta/The Pit/Point Lookout