Quick Select working fine on one computer, selecting too much on another

I recently got a new desktop computer, and I'm trying to use the Quick Select tool but it's not working like it is on my laptop. On the laptop, I can use the tool to carefully select (or deselect) aspects of a photo with ease. But with the desktop, I do the exact same thing, in the exact same spots, and two clicks later the entire image is selected. It doesn't matter what I have the brush size set to; it still does it. It's way too sensitive. Is there a way I can fix that? It's very frustrating to not be able to use Photoshop the way I want to on my new computer with a larger monitor so I can actually see what I'm doing better.