The first time you open the emulator you will have the possibility to change your resolution. when you open the configuration screen the default is the original size 800×240(2x 400×240 per eye WQVGA) and the lower screen 320×240 pixels. You can change this however it would make the screen a bit more pixelated.
There is one thing you need to do in order in order to use to 3DS Emulator. You need to have the original BIOS of Nintendo 3DS, its illegal to use copy of a BIOS. If the 3DS Emulator cant find a genuine BIOS the software wont run.
Once you have set everything up, you can play 3DS & DS ROMS with this 3DS Emulator.
Click the green download button to download 3DS Emulator now for Windows 8, Windows 7, Windows Vista, Windows XP, Windows 2000 here.