I just cant find it. :banghead:

Man I can t remeber its been sooo long. I know that I did every th ing that needed to be done there with out leaving. I didn t have high lock pick or science either because it was real early in the game and I was lost. It may not be a key,but turning somthing on or off in the building.

It may be on wiki or you ll have to wait for someone that its more fresh on their minds. I m 99.9% sure the way is in that building.

You have to unlock it on all three terminals that you shut the robots down with.

This. If you find a robobrain (the name will display as Masterbrain) wandering around the halls, kill it, and you can shut down all security in the building. Those turrets kick my butt.

There's a bug with that area. Sometimes even if you unlock all three terminals, you still can't get in to the mainframe. I have yet to make it in there. It's not that important though as all you get is the locations of the various vaults on the map, something you get anyway by playing out the main quest.

I think you can also climb up to it via the pipes from the lower part of the room.

Apparently so but it's a real pain to do. I gave it a try after being locked out but I finally gave up out of frustration.