Any changes to screen dimensions will apply to all applications running.
For that reason, plus the fact that the user may have a legitimate reason
for having chosen their specific resolution (think visually impaired users),
it's seldom (if ever) recommended that you change the resolution.
The usual approach is to resize the form to fit the user's resolution,
rather than vice versa. Check http://www.mvps.org/access/general/gen0002.htm
at "The Access Web" for a couple of suggestions.