I beg to differ... on my Win7 Laptop I can run the Command Prompt (Dos is not in Win7!) if the resolution is set really low, from memory I believe it is 640x480 or lower.
you are correct DOS does not in Win7 that's why back in windows 3.1 they started the MS-DOS which is your "Command Prompt" as you read now. Little knowledge and takes you far to know the old to understand the new.
It is now incorporated in a Command Prompt (cmd.exe) to support DOS Commands.
But not such and such as DOS in full-screen mode.
The latest Windows Display Driver Model(WDDM) does not support DOS in full screen now. Workaround: you may revert to an XP Version of WDDM if you insist still to full screen Command Prompt, or DOS, either.
But for me I do not recommend reverting to XP version of WDDM. It is really very tricky thing to do since you own a Windows 7.