There are a couple of ways to tackle this but as you do not say what Video card is installed on the Inspiron I'm not sure of the exact settings. You need to see if you can change the resolution, do this by right clicking on the desktop and selecting "Screen Resolution", then look at the  settings available. The other thing you could try is, again right click and select "Screen Res" then  Advanced settings (to the right of Orientation), on the tab "Adapter" click on the "Properties" button, now select the "Driver" tab and then click on "Update Driver" choose automatic for the update and once the update is finished, go back into screen resolution and check if you can cohoose the one for your laptop. Failing that go back into the Driver Tab and instead of update driver choose Uninstall(on the bottom) and re-boot and let the laptop reinstall the Video drivers again.