Green and purple screen when lifting the laptop?

One year old Lenovo thinkpad edge E330 that has been used to program in .net and browsing. had first time problem with this laptop Wednesday 4th of march 2015, when I tilted the laptop which i had in my knee the screen turned green/ purple and was all pixalated into blurring colors. Could not see the screen except the blurred green-purple fizz and could not shut down laptop with the start button by pressing it. Pulled the battery out and restarted it on a flat surface. re installed the OS same day.

Laptop seem to be working fine for another day and then just now I took the laptop on my knee again (lifting while on) and the screen turns green-purple and pixalated again.

Pulled battery out to restart and once on again I actually saw my old start background picture which I had before re installing the OS yesterday!

Because I saw the old picture before the computer changed back to my new background picture it made think that it must be a hardware fault.

It works well when placed on a flat surface like a table, but not when tilted which is a sign of something like a cable that is slipping then and then.

What do you think?