It took about 6 tries to boot to Windows a little while ago. First try - couldn't get the login field to open for a password. second try - got the password entered, but after a prolong period, it popped an error simply saying access denied. third try - booted into safe mode okay. fourth and fifth tries got no cursor response from the mouse, and couldn't login from the keyboard. Sixth time, reached desktop, but still no mouse. I changed the battery and swapped it around between the 2 front USB 3 connectors...no joy. The same happened when I connected using the back 2 USB 3 connectors. Finally got it to work using the USB 2 connectors on the motherboard. Don't really know if the boot problem was due to the mouse problem or if it was just a coincidence. Checked the Device Manager and it says that both of my 2 USB 3 host controllers and both USB 3 root hubs are okay and have no conflicts. Anyone with any idea of how this kind of problem comes about and how to fix it?