2Mike Koelling: X200 is a Core2Duo system. I have X61T, which is CoreDuo too, and DOS / WinOS/2 works fine.
But on another laptop, T420, which is Core i5, it does not work, Symptoms are the same: Black DOS window
with a blinking cursor. Fullscreen DOS session does not work too. Adding lines to config.sys and autoexec.bat
(as Roderick suggested) does not help too. Installing ACPI.PSD versions 3.23.1 and 3.23.5 does not help too.
The same thing is with my father's Toshiba Core i3 laptop. It seems, the problem is with Core i3/i5/i7. Older
Core2 Duo machines work fine.