I had not played it in a while and took me a while to remember it, but the way I got 100% on hard is that after cutting the elec on the fence and going by the two guards, you go up the small ladder, then the first few steps after climbing the ladder near the silo is where they were always detecting me(turning red in the low/left screen).
-So after going by the second guy and when you get to the top of the small ladder, stop there.
-Equip the sticky cam, turn around facing the two guys you just passed, and look on your left in diagonal there is a metal housing between two electrical pillars, shoot the sticky cam on it.
-When the guy right under you is on your left (closer to the metal housing with the sticky cam, use it to make noise with the X button) and he will investigate.
-time to move to the top of the silo
Note that when you get to the top of the silo, if they do not return to their normal run but keep their flashlight on, and walk slowly in alert mode, no point in continuing if you want 100% stealth because you have been detected.
Edited by sosotiit, 10 May 2007 - 03:27 PM.