I am in the 2nd of the lower levels of this tower and have gotten all the stuff from the fighting dummies, and the bedroom. That said I cant get the third door in the entry foyer to open or the secret door in the bedroom to open. I have the stones (3 plus the one from upstairs) but nothing seems to work including the statues in the first room. What have I missed.

Oh! And how did I miss out on the chess game in the upper levels?

I've played TotSC some time back, and memories of Durlag's Tower (one of the harder dungeons I've experienced) are quite hazy. I do remember getting a key to open a locked drawer in a bedroom, though. Maybe you can try downloading the walkthrough from Gamespot?

As for the chess-game, it is at one of the lower levels (definitely not on the upper floors). Have fun!