|Likely this is not related OpenOffice 4.. and if your scan comes back clean..|
Update your video driver.. Will need more info to get you a link on that (make/model of workstation and/or video card)
Adjust your screen resolution - Start > Control Panel > Display > Change Display Settings (make sure you set to recommended)
Auto-Adjust your monitor - This is done on the monitor itself.
Are you saying that when you reboot its no longer enlarged and jumbled icons? If so, is there a certain application (e.g. openoffice) when you run it that causes the screen to change resolution?