How could I solve a recurrent sudden stopping of a Lenovo 3000 N100 laptop?

Question

Hi everybody,
I have bought a new laptop Lenovo 300 N100 in November 2007.Since February 2009, it does not work correctly. The problem is the following:
  When I launch the laptop- it's XP which is installed on it- it works approximately between two abd three hours and suddenly stops.When I launch it again, it works approximately 20 minutes and suddenly stops.When I try to launch the laptop again, it  does not start ; but if I let it take 1 week of complete rest , then , when I launch it , it works approximately between two and three hours.
Please, how could I solve yhis problem?
Thanks you in advance for your answers.

Answer 1

Hi Duck3,
Excuse me to answer only now to your message; it's due to the fact that my Internet connection had problems.
When I say :
"but if I let it take 1 week of complete rest , then , when I launch it ,
it works approximately between two and three hours." , it's when plugged in (my battery no more works since November 2008, the laptop can
no more work only with battery), the laptop(when it works) indicates that the battery is "charged" at 0% and the problems I have described 
in my post began in February 2009.
I haven't done BIOS update since I bought this laptop.
                                                                             Thanks.