Batch files are an old-fashioned version of scripts. They're done via DOS command line for the most part and can be written in Notepad, Word, any word processing application. The trick is to name them with an extension of .bat at the end. .bat stands for BATch file.
http://www.computerhope.com/batch.htm is an excellent tutorial for this subject.
Some common commands available in XP's version of DOS:
call
cd
choice
cls
copy
echo
endlocal
exit
for
goto
if
pause
rem
setlocal
shift
start
xcopy
examples:
start /max c:\windows\notepad.exe - This will start Notepad maximized.
shutdown -r -t 00 --> this will restart your computer