Two ideas without code change:
1) Just set the resolution of the desktop to another value, such that it's the same as on older monitors.
2) Change the font size in the dialog resources. This will change the size of the whole dialog.
With code change:
1) Use CDC::SetWorldTransform(const XFORM& rXform)
to scale the CDC before you paint onto the CDC.
2) Use CDC::SetViewportExt(..)
, enable the scrollbars in CreateWindow(..)
, and handle the scroll events by using CDC::SetViewportOrg(..)
to move the content of the window.