Yeah, I don't want to use both. I'd like to close my laptop and stuck it under my desk and just use the AOC monitor.
What do you want to do? Use only the AOC monitor or use both the AOC and the laptop screen?
If you only want to use the AOC you should be able to turn the computer on with the AOC connected and then close the lid of laptop. This should use the AOC as your monitor.
If you want to use both Extend is the only option that will give you a clear picture on the AOC. If you Extend you can set the AOC as the main display.
I believe that some laptops will allow this while others may not. Some laptops will just automatically go to sleep when you close the lid with not option to set it otherwise, I believe. So, it is possible that you might still need to leave the lid slightly open.
I'd only like to use the AOC which I can, but the problem is when it's not in Extend mode (aka display 2 or duplicate screen), the picture on the AOC monitor is fuzzy and not crisp like it is in extend mode.
Then you likely want to set the "screen mode" on your laptop. It should be done with one of the function keys (it will depend on the brand and model of your laptop). What is your laptop brand and model? The function key will have a little icon on it that looks like a monitor. You will then hold down the "Fn" key and then hit that function key. It will either then toggle through the options or pull up a menu on the screen. Typically, you can switch between laptop screen only, external monitor only, and both screens mirrored.
I am making use of this ability with a friend's Dell laptop where its built-in screen's back lighting died. In the case of this laptop, the function key to use is the F1 key. And it pulls up a menu on the screen to select which option to use (which is was very hard to see since the backlight is dead...I was used to past laptops just toggling between modes, so it took me awhile to figure it out since I could not easily see the screen contents).
If you use the external monitor only option, then the screen resolution may default to the optimal screen resolution. If not, then you will have to change the screen resolution as Kilroy
If you set it to mirror (as it seems you have been doing), then one of the two screens will be fuzzy. This by default will typically be the external monitor as the system is typically set to your laptop's native resolution. So, unless the external monitor's native resolution is the same as your internal laptop's, the external monitor will typically be fuzzy. You might be able to set the resolution to the laptop's native resolution will in mirror mode, in which case the laptop's screen will now either be fuzzy or maybe oddly stretched. I know I can do such things with my Macs, but I am not sure if there are limitations for some (or all) Windows laptops.
Your last option would be to just use the extended screen mode and set the external monitor as the main/default screen. This will result in the "Start" menu being on the external monitor and have things open by default on the external monitor when it is connected. When it is not connected, you laptop should work as normal. I forget if you will need to reset the external monitor as the primary each time you reconnect the laptop (I don't need to do that with my Mac, but I forget if Windows behaves in the same way). And with the option, you can then also use the laptop screen as an additional screen if you want. This is how I have my Mac laptop setup. I use my larger, external monitor for pretty much every thing, but do have some things left open on the laptop's screen such as my calendar application for constant reference if needed.