When i turn on my laptop, windows open
and after 5 minutes the screen goes blank and fan starts spin and laptop didn't shutdown even i press the power button only possible is remove the power and battery from the laptop and sometimes it works fine for 1 to 2 hours and sometimes not even open the windows, please suggest me what is the problem with my laptop
I have a problem with my laptop lenovo z460
Vetrivel
Windows by any chance? Your problem is Windows has crashed, so your going to have to reinstall the operating system again Windows crashes is/has been a problem for the passed 28yrs since the days of W98. Nothing has changed only the screens which used to be know has the BSoD (Blue Screen of Death) then it moved to the BSoD (Black Screen of Death) Now it's the BSoD (Blank Screen of Death)
Why don't you move to the Free Linux Open Source Operating System that Lenovo Support and Develop. Check out the web links below then you will see for yourself who the 210 worlds top hardware manufactures are that develop the Free Linux operating System
Picture of Deepin Linux Desktop Works Looks like the mac desktop. 
Carling