In act 2, you are supposed to find an ID card in the underground lab. After getting the ID card, you gonna need to go back out of the underground lab and open a secret door thats in the first room with alot of computers. From there you should be on the right track on your own. If you get to a point where you have to press switches and two snakes roaming the area, you basicly almost done with act 2.
@fagerbrandon81
The room that says "You see a 'A' letter on the lock" means that you need a key for that room. Be sure to check your keys you collected.
When you talked to the read head you should by now be heading to the underground lab. In there you need to collect keys/ cards that open specific doors. You might have missed them.