i tried f10...saved the changes and exit. but again it's the same issue. please help. thanks in advance

Uhh, from the limited information you provided, it sounds like your boot configuration is messed up. You may need a new hard drive. Can you be more explicit. It is difficult to help with such little information.
 
Actually the battery was down and laptop switch off.
i left it to charge and now when the switch it on, i am getting the "Press the Esc key for startup menu".
Please help. i have to submit my work my end of this month.
Thank you in advance
 
oh no you have work on it i was just about to say that your hdd is posibly corrupted , if you have another pc then put your hdd in that and try to get your work back (you will need to get past the permissions