Lenovo G580 , won't boot

First of all, you need the present password. Then straight after turning the computer on you press F12 or insert multiple times after each other. That way you will stop the normal boot and enter the BIOS settings. There you most likely will be prompted for the password and then under security you can disable or change it.

Sounds like a bad monitor or ram. Does the hard drive, fan etc make noise when first turning it on?

If there's noises indicating it's working, it's probably a hardware issue.

I would reinstall the keyboard and mouse drivers to be sure.

Lenovo Support Drivers Software US

of course window has not the function to fix such an issue, you can get it on work again by restore your system, or download a tool like Windows Boot Genius to fix the issue,it is effective.

This could be a case of overheating.
First question, did the no signals sign appear out of the blue?
Check inside for melted components.
Clean your computer, remove all dust.

Check back with me.

Press F8 during boot, and load Safe Mode. A program may be preventing a proper startup.

Try disabling startup programs. Go to Start > Run (search in Win 7) and type MSConfig > Startup tab and uncheck anything that you don't want Windows to load automatically. It will make Windows boot faster and use less resources while running.


This just disables them in startup. Programs will still load, but when you initiate.