[Mighty Midget]

to manually start a game in DOS, you need a couple of DOS commands that you type in the DOS prompt:

cd
(change directory, equals clicking a folder in windows) followed by the directory's (folder's) name.

[filename of either the game's exe-, bat- or com file]

Example:
You have Colonization (start file = colonize.exe) in a directory called Colonize, which in turn is in a directory called MPS.
In the the prompt showing C:\> type
cd mps
cd colonize
colonize

The last command (colonize) will start the exe, bat or com file named "colonize".

If you enter the wrong directory, type
cd ..
to go one step back in the directory tree.

Another helpful command is
dir
which will display all files and directories in the current directory.
dir can be used with the /p switch to list the files and directories one screen at a time if the list is long: dir /p
One last thing. When looking for a particular file extention, you can type
dir .[file extention]
e.g. dir .exe