it seems like your computer is missing some booting files or it is infected by viruses. so first of all we have to try to open "advance boot media option on your computer" . for opening an advance boot media option you need to keep tapping "F8" button while you are restarting your computer.
If your computer comes on advance boot media option, you need to go on safe mode and then you need to scan your compute with the good antivirus and you need to restart your computer in normal mode.
if it is restarting it then it is ok. if it is not restarting it then you need to restore your computer on back date when it was working fine.