If you have Tweakui, open it up, then goto the startup tab. Uncheck "Start GUI Automatically".
(If you don't have Tweakui, then you'd need to edit msdos.sys and change bootgui=1 to bootgui=0)
Once this is done, the computer will boot into Dos by default. Windows can then be launched by typing "win".
One way to automate this process would be to edit the autoexec.bat and add the following lines to the end:
CHOICE /N /C:12 /T:1,5 Boot Into Windows? [1-No, 2-Yes]
IF ERRORLEVEL == 1 GOTO END
In this example the choices are 1&2, the default choice is 1 with a timeout of 5 seconds
This should get you started. It won't display anything on the lcd. For that you'd need to use a third party program, like LCDPrint.