I pity on you.
O.k
For the problem.
Start your computer, click right click anywhere on the screen so the menu comes, click on the properties button. Go to settings.
There will be a scroll which would normally be on 800x600 pixels or 640x420 pixels. Drag that scroll until you see the resolution rmxp needs.
Or in other words, go to control panel, display-desktop-settings-dragt the scroll to the required resolution.