All tools drawing automatic diagonal line up

Hello,
I recently began using Photoshop CC 2021, and am having real trouble using any of the tools.
I'm on Windows 10 Home, a Dell Inspiron 7506 2 in 1 laptop.
As soon as I click on an image, the tool draws an immediate automatic line up and to the left as if I had moved my mouse in that direction. Once the 'line' is drawn, I can then move the cursor/tool as expected, but this is obviously useless when I'm no loneger where I want to be, and there's now a large undesired line in my image.
This happens whether using mouse or laptop trackpad. It happens whether using eraser, brushes, spot healing tool, etc.
I\ve tried turning of Graphics Processing, and the various Advanced Tools related to it, but not sure what else to even try, as this seems really odd and sadly makes Photoshop useless for now 😞