GIMP should allow you to do that.
It has a lot of the functionality of Photoshop, but for free.
Yes, GIMP is perfectly able to do this and much more, but with good old MSpaint that comes with every windows computer this can be done too!
1 Just open two mspaint screens (windows button+R, type mspaint, enter, repeat),
2 open the image you want to crop in one window,
3 select the the area to crop to with the select tool,
4b go to the second mspaint windows,
5 click outside the edges of the screen in the grey,
6 resize the drawing box to area very small (drag one of the small squares all the way to the upper left corner), paste and save, in your desired format.