This is the forum for helping you out if you're stuck or if you want to discuss the nitty gritty details of the dungeons within Mount Grimrock. Warning: forum contains spoilers!
About the second one, if you're looking at your map you'll see that this room shares a wall with another room. The hidden switch is in that other room.
Allright, so about the first one...it doesn't open.
SpoilerShow
So, I have to stand where those dragons look. I found the both dragons and marked the point on the map where their lines of sight would cross. I have been resting and waiting there for a good amount of time. How long do I have to wait?
Or does it mean that I have to wait first in front of the first dragon and then in front of the second one?
[insert quote by popular deceased person you read somewhere]