Test to see if it's software related by booting to all the Windows SAFE MODES (see the web on how) and then if they fail, try getting to the BIOS SCREEN and see if that works.
The Lenovo G580 screen will turn off when I plug in the charger. It will still charges the battery but I cannot use it when it is plugged in. The battery lasts several hours so I believe it is good. I checked the sleep mode settings in the power options and they seem OK.The Lenovo G580 screen will turn off when I plug in the charger. It will still charges the battery but I cannot use it when it is plugged in. The battery lasts several hours so I believe it is good. I checked the sleep mode settings in the power options and they seem OK.

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