0251 system cmos checksum bad

Hello,




i have a hp compaq presario v3000 laptop which is 2 year old now.
from past two months I am getting a error on the bios post screen saying
SYSTEM BIOS SHADOWED
VIDEO BIOS SHADOWED
0251 : SYSTEM CMOS CHECKSUM BAD LOADING THE DEFAULT CONFIGURATION
PRESS F1 TO CONTINUE

the message comes once in 10 times I open the laptop
otherwise from 2 months when I switch on the laptop the laptop fails to boot and the system do not proceed from the post screen .
so in order to boot the only trick I keeep on using which is not good is
i used to switch off the laptop 4 or 5 times directly.
then I remove the laptop battery twice and after doiing this laptop boots up .
i am doing it for past 2 months and culd not find any permanent solution.
also the laptop is heating beyond 100 degrees within 10 min.
so what should I do where is the problem.