Hi BlackHawk,
Installing Windows 98/2000 (or even XP because it allows Command Prompt to go full screen) would work perfectly. However you have to go to all the time and trouble of installing the OS. Although 98 is now pretty much abandon-ware, you still need to have a genuine license. However I have a copy of DOS 6 running on Microsoft Virtual PC which I downloaded easily off the Internet. You may as well just use this instead. DOSBOX however is smaller (but not easier!).
There is a way of getting Command Prompt to work in full screen in Vista, but I really would not recommend doing it so I will not provide exact instructions. If you want them post back.
The "Windows Display Driver Model" (WDDM) no longer supports all DOS Display modes, and it is for this reason that you can no longer access full screen mode. However you can install the XP Version of your Graphics Card Drivers from ATI or nVidia etc or the Standard Microsoft VGA Drivers (not WDDM). This almost always causes regular random crashes of you computer and will disable Windows Aero. Why ruin your computer (albeit until you reinstall your Vista drivers) so you can play an old DOS game until your computer crashes again(!)?
There is a way of making Command Prompt fill your screen, i.e. maximized, but it is ridiculously complex and not the full screen a DOS game needs!
To do so:
(As a one off)
1. Open an Elevated Command Prompt.
2. Type "wmic" without the quotes and press enter.
3. Maximize your window using the middle of the three buttons in the top right hand corner of you Command Prompt.
4. Type "exit" and press enter, DO NOT press the red X.
N.B: You may have noticed that this method gives you a bottom slider!
(Always until you undo it)
1. Open an Elevated Command Prompt.
2. Type "wmic" without the quotes and press enter.
3. Maximize your window using the middle of the three buttons in the top right hand corner of you Command Prompt.
4. Type "exit" and press enter, DO NOT press the red X.
5. Right click on the top bar where it usually says "Administrator:Command Prompt".
6. Select "Properties".
7. Click OK without doing anything.
8. Type "exit" and press enter.
N.B: You may have noticed that this method gives you a bottom slider!
(To undo it)
1. Open an Elevated Command Prompt.
2. Right click on the top bar where it usually says "Administrator:Command Prompt".
3. Select "Properties".
4. On the layout tab set the following values:
SCREEN BUFFER SIZE:
Width: 80
Height 300
WINDOW SIZE:
Width: 80
Height: 25
6. Click OK.
7. Type "exit" and press enter.
N.B. You can also use this method to set the window size in the first place.
Richard