Mac book pro turns off when moving the lid? Still paying!

so i bought a MacBook Pro (13-inch, Mid 2012) about 1.3 years ago from the apple store.i am still paying for it since i financed, and my warranty just expired . Every time i move the lid, mac is shutting off. so i didn't open the mac for a day, i tried it again , seems to have no issues for about half an hour, then same problem starts again. once it starts, i just have to slightly move or shake the lid, mac completely shuts off. i did a hardrive diagnostic , came clean, i did couple of resets that was floating around in forums, no change.. I have a Kingston ssd hardrive and i replaced the cd drive with hardrive that came with mac. i did this about 8 months ago and this problem just started to happen. i did had a case for a long time, case got dirty, so i removed the case and ,i am not saying that's what did it, but after a day i took off the case , problem started to happen, i know that's sounds stupid ,but just throwing it out there, its just a regular plastic case i bought it off amazon. mac is really fast, boots up fast, mostly cuz the os runs from the ssd. so no problem with speed.