Can't find last key

i have found all the chips and keys, except the last key... it is suppossed to be in the 'surveillance room' but for the life of me i can not find the dang thing... any help would be appreciated...
thanks in advance
gram

still can't find it and i am on level 21...

never mind.. i found a cheat site... too bad it was after i got to the riddle at the end, sigh