MSI CR500 shut down error

I have recently been given a laptop by a friend who no longer needed it. He only had it for just over a year before upgrading as he found he had some problems with it. The laptop is made by a company called MSI, I have never heard of this company before but it seems they are a relatively big company who ake a wide range of laptops. My laptop is the MSI CR500, it is a pretty decent laptop with 3 gb of RAM and a 500gb hard drive. However when I recieved the laptop it would only switch on when it was plugged in and would only stay on for a limited amount of time before shutting itself down. I am pretty confident with fixing computers so decided to open it up and have a look. I took all the main parts out and cleaned them, I cleaned all around the motherboard. I thought the source of the problem may have been overheating so i decided to clean out the fan, when I opened it up I saw a huge pile of dust and after removal thought this may have solved the problem of constant shutting down. When I powered up the laptop, it stayed on for a considerable amount of time and is now staying on for as long as I need it. However the other problem is still not fixed, although it still needs to be permanently plugged in (which I am fine with). The problem is that when you move the laptop it shuts down, this has lead to me having ot use it on a still surface all the time. This problem has been there since I got the laptop and am now stumped. Does anyone have any idea what could be wrong with my laptop shutting down as soon as I move it?

 

no idea whats causing a shutdown when mooving,only thing i can think of is something is lose.

you need to monitor the temperatures and you can find free software in my sig below.
if possible could you also tell us what processor it has and if it has a intergrated graphics card or a dedicated nvidia or ati card.