The software is built on Delphi 7.
On my XP machine, the form resizes as I expect. However, on two Vista machines, I have components with anchors set to [akLeft, akT
It might be because of the transparent frame which is shown by Vista. (In order to give different windows same transparent appearance.
Try using "Align" (alClient) instead of anchors. Since you are using all anchors, that makes more sense.