Cannot adjust monitor resolution after downloading game

So, a couple of hours ago I downloaded and installed the game at this link: Download and play free game: Super Mario Bros. 3 | Classic Retro Games and started playing it. When I opened it, the game went straight to full screen, and I couldn't figure out how to downsize it, so after screwing around with it for awhile I just shut the computer down.

When I restarted, my monitor resolution was, I don't know, one? two? It's so distended that I can't, for instance, right click, select properties, and adjust the resolution, because the toollbar takes up most of the screen and the mouse refuses to navigate above it.

Restarting doesn't work, nor does adjusting the resolution in safe mode then restarting. Display in safe mode is normal.

So tell me--what's a girl to do, besides light the whole thing on fire?

Try "Last known good configuration" in the advanced boot options menu if you havnt already. Otherwise maybe run Malwarebytes in safe mode to make sure you dont have a virus of some sort. Just a couple ideas