My laptop lenovo g580 turning on but only shows lenovo logo. Then not working?

The real reason your computer won't boot up is because the MBR (Master Boot Record) is corrupt Without the MBR windows can't boot up. You will need to reinstall windows again. If you don't have a windows install disk then your out of luck, your going to have to buy one, or download one of the latest July 2014 Free operating systems, I recommend you take a look at this free operating system that was released this week. You can check it out here, this is just one of the top 50 free operating systems that's available to you.
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Hold down f8. See if you can get any prompt that way. If it still does the same thing then try entering the bios. If you can enter the bios then your computer is likely savable and it could be a component has gone bad.
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See if you can enter bios setup and try loading defaults. If that doesn't work try a restore process next. If that doesn't work you probably need a new drive.

Go to Safe mode and see do a complete scan