Hi, MSX fans !! For all who are blocked in Solid Snake : "For entering in the second building you don't need the 4th card :) you just have to stand next to the conveyor belt (the right screen to the entry of the 2nd building) and then tranform yourself in a box and after a short time (normally !) a guard will put you on the conveyor belt who will transport you into the 2nd building :DDD The 4th card is in possession of Horry White who is prisonner in the sewer of the 2nd building, you need to explode a wall to deliver her. Well that's all i remenber :)" If you need more details feel free to ask !! Bye, David.