Two comments:
1) Hopefully you're not using the free Houdini 1.5a, because that free version can't run at reduced elo levels; It always runs at full strength.
2) Assuming you're using a UCI engine capable of running at reduced elo levels --
a) The elo ratings in the game data window don't actually change the engine's strength. Those elo numbers are just for your own use.
b) To reduce the engine's elo settings, you have to go into the engine configuration window and change the engine setting there. The Help file will explain in more detail.
I just downloaded chess area 3.0 to try and analyse my games and play against the computer sometimes but I load the engine, go to game data and set the computers elo to 1500 but when I start a game, the elo changes back to 2000 and it computer is an absolute monster of an apponent...
How can I set the computers elo to a specific level? I installed houdini but again it's playing on the best settings possible and I can't change it.