Change location for opening windows

We have some dual monitor worstations two 17" LCD's side by side. We are getting complaints because when working through an application different dialog boxes open right in the middle of both screens. Half of the prompt appears in the left monitor with the other half appearing in the right monitor. Is there a windows setting that I can change that controls where these boxes\windows open? I would like to change the settings so the dialog box opens in the middle of one of the displays.