1) I want to throw it out the window

2) I want to throw my laptop out the window

3) I want to throw out my laptop of the window

Is #3 incorrect?

Question

1) I want to throw it out the window

2) I want to throw my laptop out the window

3) I want to throw out my laptop of the window

Is #3 incorrect?

Answer

You answered your own question. The first two are fine, but the third one doesn't work.

Answer

3)  I want to throw out my laptop through the window.

Answer

What is your "laptop of the window"?  Before you tell me you are throwing it away, you need to tell me what it is.  Perhaps you have three laptops: one that you keep on your desk (the laptop of the desk), the one you keep in the bathtub (the bathtub laptop), and the one you keep by the window (the one you are throwing out).

Answer

I want to throw it out the window ☑️