Pls help.
I try to launch the game, but almost nothing happens.
The screen blinks, then goes black, sometimes rescales for a second, but after that it returns to desktop.
Any ideas what should I do?

See if anything from this thread helps (such as running the game in windowed mode):
http://static.gog.com/forum/gabriel_knight_series/gk2_dosbox_crash_when_launching_gk2