I'm using a Dell Inspiron desktop computer hooked up to an old Venturer monitor. When I go to change the screen resolution under Personalization, Windows won't allow me to make any change from 1024 x 768, which won't work (the right side of the screen is missing). It doesn't even seem to detect the monitor. Can I manually make a change to resolve this situation?
It seems you are having a driver problem with your graphics card, not with your monitor. Try to get a driver from the official site of the manufacturer of your graphics card and install it, then see if it is OK.
Another thing you can try, is to see if the settings of the monitor itself are messed up. Try to reset the settings of the monitor by using buttons on the monitor itself.