Recently i found my system variables changed and some of the commands are not worked in DOS.
‘ping’ is not recognized as an internal or external command,
operable program or batch file.
Solution for Windows XP:
Right click “My Computer” and click “Properties”. Click the “Advanced” tab up top followed by the “Environment Variables” button at the bottom. In the 2nd list box, scroll down to the 5th or 6th entry “Path”, select it and click “Edit”. Add
to the beginning of the line. Okay the changes and try out your commands now.