Are you using _Zenger_'s patch? Yes,i'm
What resolution are you using for the game? 1366x768
It looks like what's happening is that your graphics card scaling isn't working. If you're running the game in its original 512x384 resolution, it's likely that your monitor can't go that low and is defaulting to something like 640x480 and then displaying the game in the middle of the screen in a 512x384 box.
If you are using _Zenger_'s patch to increase the resolution and you are still seeing the game running in a small box in the center, then you should check out your graphics card scaling options. Go to your Nvidia control panel and look for an option that says "flat panel scaling" or similar. Make sure that scaling is turned on (the best setting is probably the "preserve aspect ratio" setting which will prevent games from getting stretched and distorted). That should enable the game to be expanded to fill your screen.
Even if you are running at the original 512x384 you might want to check the scaling options anyway... it will probably still run in a box but you might be able to make that box larger.