monitor problems

I have a Samsung 245BW and have had lots of problems keeping this thing calibrated. I seem to have managed to get the colors pretty close using Adobe Gamma but my exposure seems to change when I look at my images every other time I start the computer.?? I have tried to use my Eye 1 Display 2 and that has given me terrible results with this monitor. I"m close now but can't figure out why the images would look darker one time and back to the right exposure the next time. Anyone having the same problem or have some advice on some settings for the monitor? Thanks