Encontrei uma correção nos fóruns da Lenovo para um problema que considero igual ao seu problema. Aqui está o link: Tela preta Y560 após o arranque
E aqui estão os pertinentes:
I would like you to uninstall the ATI driver via safe mode, then boot into normal and try to cancel off the installation. if you're able to cancel the ATI driver installation in normal mode, kindly try the following steps.
- Go to system properties
- click on "Advance System Properties"
- click on "hardware" then on "Device Installation Settings"
- select radio button "No, let me choose what to do"
- select radio button "Never install driver software from Windows Update"
- click Save Changes. once the above is done, restart your system. The steps above is to stop the computer from auto-installing, now go to http://support.lenovo.com and do an update of your computer.
Espero que isso ajude.