PS7 Win - images dark on LCD monitor

I'm using Photoshop 7.0.1 for Windows, under Windows 2000. A blown CRT was recently replaced with a Samsung Syncmaster 191n LCD monitor. Since then, images look the same as usual everywhere but in Photoshop; in PS, they are very dark.

My normal color settings are Adobe RGB, US Sheetfed Coated v.2, and 15% dot gain for grey and spot color. RGB, CMYK, and grey images are all converted to the working space.

I've gone through Ian Lyons' instructions for the color setting, to no avail. I've tried making random changes to the settings just to see if anything would change the images appearance, but they still look extremely dark. If I adjust the images (using Levels or Curves) to look good on the screen in PS, they're far too light in PageMaker and when printed.

I've also manually adjusted the monitor settings, although the interface is confusing (color temp settings don't actually show any color temps such as 5000, 6500, etc.), but the images in PS still look dark even when monitor brightness is set to the maximum. Any suggestions? Keep in mind that this problem started only after the LCD monitor was installed.