Here are some things you can do:
1. Find the small Novo button on the left side of the laptop. It's right next to the memory card slot, and you need to unfold a paper clip to press the button. This button will bring up a very basic menu with 3 or 4 options, one of which should be System Recovery. Selecting this option will restore the laptop to its factory settings.
2. If the laptop has been unused for 2 months, you might want to recharge the battery. Plug in the laptop to the wall socket and let it charge for 3 or 4 hours.
3. Some times simply rebooting the laptop 4 or 5 times may kick it back into life. Press the start button to activate the laptop, and after 20 seconds hold the start button for 8 - 10 seconds to shut it down. Repeat this process until the laptop boots up properly.
4. Finally, if the screen seems to flicker with black and blue screens, it is most likely a screen malfunction. If the laptop is still under warranty, you should contact Lenovo in your country for a replacement screen.