Lenovo n500 not starting?

My lenovo 500 laptop turns on but goes on lenovo start page then goes black and back to lenovo start page and keeps doing that. My laptop has been slow for a few days and I did a disk clean and deleted all my cookies on internet my laptop ran out of battery and since trying to turn it on its just doing that. I have no disks for it as its my grandmas old one and she lost all the disks any help?

Hi sorry wrong section computers and internet is the right one.
but to save time take it to a tech.

And the computer you used to post this question foolishly placed it in the section for Cars and Transportation, Maintenance and Repairs.

No installation discs then no chance