This question applies to Stargunner, MegaRace 1 and MegaRace 2.

I wasn't sure exactly where to post this as it is more of a DosBox related question since it involves 3 different titles.

Currently when I launch Stargunner it opens as if it's going into fullscreen mode but then the window changes into windowed mode when the game actually starts. This exact behavior happens with MegaRace 1 and 2 as well.

I have used the DosBox Graphic Mode Configurator and the Full Screen box is checked. I have also tried OpenGL, Overlay, DDraw and Surface for Graphic mode options but the result is always the same.

Also, in Advanced Settings the Window Resolution is set to 1920x1080 (which is the aspect ratio of my monitor) and I have tried checking/unchecking the Keep Aspect Ratio box but it is always the same result.

I simply want to play this game in fullscreen and maintain its original aspect ratio.

Any help would be much appreciated.

Doesn't ALT+ENTER work?

EDIT: Open the game, if it starts in windowed mode press Alt+Enter.

I should have mentioned that I have tried that before. The problem is that it doesn't technically start in windowed mode. It starts in fullscreen mode but then reverts to windowed mode because for whatever reason it won't stay in fullscreen.

Pressing Alt + Enter attempts to put the game into fullscreen mode but then it reverts back to windowed mode unfortunately.

Must be something to do with your system. I just tried it and it ran full screen (looks pretty good on full screen too considering it's age). But since I know nothing about DosBox I've never changed anything so at "default" it works full screen on mine so I'm thinking maybe it's a system issue rather than a DosBox issue?? Maybe even a monitor setting perhaps???

ADDED: Oh and in my video settings i have keep aspect ratio selected as well.

Do you mean real windowed mode where you can see the desktop in the background and even move the unfocused game window around, or do you mean "windowed" as in the game screen in a tiny stamp-sized "window" in the middle, with black on the sides and top/bottom?

And what OS? Windows 10?

I do have an AMD graphics card actually (Sapphire Dual-X: Radeon HD 6970).

To respond to timppu's inquiry I mean real windowed mode where I can see my desktop and even move the unfocused game window around. It just seems that something in my system is refusing to let the game run in fulscreen mode.

Also, I am using Windows 10 yes.

I figured out what it was thanks to MadalinStroe's AMD Catalyst suggestion.

In the AMD Catalyst Control Center -> My Digital Flat-Panels -> Properties (Digital Flat-Panel) there is a box under Image Scaling Preferences called Enable GPU up-scaling that was checked. Beneath that Scale image to full panel size was selected. When I changed this to Maintain aspect ratio the game started up properly without issue.

Thank you everyone for your assistance!

I'm glad you managed to fix the problem. Happy gaming!