I picked up Empire Earth 2 from
gog.com but was having some issues with multiple-monitors. After a bit of googling I came across a solution from someone going by galatei at
neoseeker. Add the following lines to the config.cfg (or config_EE2X.cfg for EE2:TAS):
g_bFullscreen = 0
g_allowWindowedMode = 1
g_ConstrainCursor = 0
s_windowXOffset = 10
s_windowYOffset = 10
s_adapterIndex = 0
Worked for me in single player mode.