Thanks Jean - the screen resolution is fine. This is a matter of tweaking the settings Jean has suggested. If you slightly reduce the size of the wheel, and re-centre it you should be fine.
Go to the menu options->settings->layout tab. Use the button Jean has highlighted. If you want to re-centre the wheel vertically use the option below the main column. The relevant setting can be changed on the lower horoscope center up/down button.
I hope that helps. Ed