I have some older DOS games that I'm trying to run on Windows Vista, and whenever I try to load certain games from Windows or the command prompt, a box pops up that says " This system does not support fullscreen mode " with "16 Bit MS DOS Subsystem " at the top of the box. I never had a problem running these games from XP. Is there a fix for this ? If not, how to I go to a command prompt when booting Windows, you know without actually starting Windows and then selecting command prompt from the accessories?

The Answer by Praetor Maximus :

Try DOSBox.

http://dosbox.sourceforge.net/