THOSHIBA SATELLITE PRO L10 shutting down

hi ive got a bit of a wired problem here ive got a toshiba satellite pro L10 and when its switched on if you move it side to side or back and fourth the hole laptop not just the screen, it will start to log off and shut down, and when i start to close the screen it trys to boot back up quite funy,
so i started by removeing the wireless card, no joy..then i swaped over the memory into another slot no joy..then i removed the main battery pack and just ran on main d.c still no joy, i checked through the bios settings but there is very little there to change on this model ,so i think somethink must be loose inside but any ideas or thoughts on this would be great thank you,

p.s the cpu fan also works and spins fine,

hi there thank you for your reply, yea the battery runs for around 40 min if i pull the mains out fully charged, but i did notice that if i was to harf way close the screen, it turns its self of aswell so then i was thinking maybe it could be the cable or conector from the screen ,but all picture qualty is fine, the adaptor is a liteon thoshiba pa3396e-1aca output 19v i havent got a multimeter but i will get it tested in the next couple of days see if the reading are right,