Crop Tool Has a Mind of Its Own

Every time I try to crop a photo, either using a preset size such as 6 in x 4 in or using No Restriction option with Custom settings of W: = 4in; H=4 in (needed 4"x4" size for my scrapbook), I try to "draw" my selection box around my desired area. Upon releasing the mouse, the square box proportions are retained, but the resulting size is either larger or smaller than my desired size. I try to drag the corner of the selection tool to enlarge or decrease the size, but the selection then jumps to another random area of the photo & changes dimensions even again. It used to be the only way to fix it was to exit and reload PSE, but even that is no longer working. At this point, I am unable to crop any photo. Any help is much appreciated.