Check the stone plates for hints. The walkthrough has the solution at the bottom, in the FAQ section, if you don't want to search for the right combination yourself.
I've had the right number of buttons pressed 7,8,9 and10 and all four switches flicked and nothing, driving me nuts. the pillers just flash red, but the crtstals remain in place. If you press on the blue mark it just resets. A diagram in the walkthrough would help, overkill perhaps but it's getting ridiculous
You select the correct number of buttons first R7 B8 Y9 G10, then flick the switches, I did then R, B, Y then G (don't know if that matters - probably not) you'll hear a crash of the crystals breaking, and you're in (phew).
