Hi, thanks for going through my question.
I am using Win10 with LPC51U68 microcontroller. After I plug in the board to my laptop, my curser is out of control, starting moving in a square. Anyone has similar issue? Please help, thank you!
From your description, the possible reason is that there is USB HID mouse demo loaded in your 51U68 board which manipulate your mouse.
You can solve this issue by erase the FLASH or download new image.
If you can’t move your mouse now, connect your board in ISP mode (thus your application code won’t be up), connect it with IDE and erase FLASH. Thus will resolve the issue.
Have a nice day,