Why is Photoshop changing my selection area?

I'm a longtime Photoshop user but new to the current version and first time using it on my Lenovo Thinkpad. When I use the rectangular marquee or crop tool, after I release to finalize the selection area, Photoshop automatically moves it to a completely different area and changes the size of the selection. Also, while I'm selecting, it like flips back and forth between where I am and other areas in the image. Even if I wait for it to flip back to my desired area/where my mouse actually is on the screen, as soon as I release my finger, it flips to some other area and size. And these are just JPGs (multiple files, same issue). I have already turned off the Snap to feature and reset all tools to default settings, same problem. I can find nothing online, and Photoshop pulls up nothing when I search for auto-select. I have no other problems with this computer whatsoever. What is this??