1280 x 800
Are they messable with? I've only ever changed it once to play some old Speccy games and it whazzed up my lappy no end!
Yeah, they're messable with. You can move the slider in the window where you saw your screen resolution to enbiggen or ensmallen (technical terms

) your display. You should click Apply, not OK - it will then give you a little message asking if you want to keep the new setting (which you can see) and will revert to the old one if you don't say yes - this stops you from choosing a setting you can't see! To be safe when doing this, select the option (if it's offered to you) to apply the setting without restarting the pc. If the option isn't offered, it should do what I described anyway. Don't click OK, this will apply the settings without giving you the chance to change your mind if you select an option the monitor can't display. This should ensure you don't whazz up your lappy!
If you want to play completely safe, click on Advanced, Monitor, and tick the box marked "Hide modes this monitor can't display" if available. That'll stop you choosing anything you can't see. You could also click on Advanced, General, and tick the box marked "Ask me before applying the new display settings." These options may not appear on every machine.