Whenever I hit my laptop or put pressure on it, it shut down. How should I fix this problem?

I have found 2 similar problems to your not same computer or brand but problems. They are quoted below

"This is probably a long shot but maybe the connection for the reset/power button is somehow getting activated when you push down on the case. Perhaps when you took changed out the components something is a bit pinched around the reset button in the case and thus any downward pressure is being registered as pressing the reset button (Maybe even something is lodged in there and thus making it very sensitive to any flex within the case frame).

I don't play around with these settings much but I think there's a way you can adjust how long the power / reset button needs to be depressed to cause a hard shut down. Maybe you can bump up this time and experiment if you have to apply pressure longer to get the hard shut down.'

Option 2

" Mine would shut down when the computer was bumped and after many, many pokes and prods and shut-downs, I narrowed it down to one side of this cover being the culprit. After removing the cover I found the problem. There are two small tabs, one on each side of this cover in the center. These are just guide tabs and are unnecessary. They are too long and they press up against the motherboard when the cover is secured all the way down. Break the tabs off and your problem will go away.

May be because of loose connection or ram problem. Just give to service.every thing will be perfect!

Man goes into the Dr. Waving his arm around saying, "Doctor, doctor, it hurts whenever I move my arm around like this." The doctor looks at him and says, "Then don't move your arm like that anymore." (Courtesy of Groucho Marx)

I think for a start try not hitting your laptop. BAM! Problem solved Phaggot