Dell Laptop C610 not booting at times

I have been using this dell laptop C610 at two different places and giving differnt behaviour. while at office it may work fine after several attempts of switching on in the morning, once on it will be working fine for the whole day including attempts of turning on and off again.
On the other hand when I take it to my place of residence, it will only work for that day and never again. I have changed the battery and cmos battery but the problem remains. I can’t use it it at home and at office difficult turning it on at the first attempt of switching on. what could be the possible fault with this dell C610.