Debug has been included in every version of MS-DOS as well as Windows. When running any of the debug routines it is recommended that if you have Windows that you exit or shut down to get into a real DOS prompt (unless you're running Windows ME, Windows 2000, Windows XP, or later versions).

Once at the MS- DOS prompt, run through the below example, this example is perfectly fine to run on any PC Computer running MS-DOS / Windows and will not harm anything.
Type debug and press enter.
This should get you to a - (small dash). This is the debug prompt.
At the - type d40:00 and press enter; this will return several lines of information.
After the feedback you will be back to the debug prompt.
To exit out of debug type q and press enter. This will return you back to the MS-DOS prompt.

In some of the below debug routines you will notice that a "g" is typed, then "q". G tells the computer that the code type is not self executing and must be run at this point. If completed, the program will return Program Terminated Normally which indicates you can now quit from the debug program.