Today or tomorrow i will receive a new Logitech mouse and keyboard.Maybe that will do the job.
I just don't think it has anything to do with the mouse or keyboard. Do you have another PC you can test it on?
Completely removing the security package then rebooting so you're just using the microsoft security software is worth trying. So remove, reboot, try some test downloads, then re-install the security package and see where it starts to fail.