Ok so every time i play my fallout 3 it shuts off my laptop automatically after 10 or so minutes of playing....

Why is this? Ive played well into the game and this has only happened recently...

Could someone help me out please?

Sounds like a heating problem. Download a program like speed fan or something of your preference that will tell the temps of your CPU and Video Card/Gpu. Test when it is idle(not doing anything with your computer), and when it is under load(preferably when you are playing fallout 3.) If overheating is the problem, then your laptop is running REALLY hot for it to shut off. The only other thing I can think of is power supply not being adequate, but that shouldn't be a problem in a laptop that is built with constant specs in mind. It could also be software based, and whatever is causing it is specific to fallout 3. Did you try any other games?

if i turn down the graphics will i be able to play?

That could help a little or in the short term, but it doesn't sound like it is a problem where you have the graphics too high. Usually that will only cause stuttering or a crash of the game not the turn off your PC.

What are your laptop's specs? How old is it?

http://download.cnet.com/SpeedFan/3000-2094_4-10540297.html

That is the program that I mentioned about measuring your Cpu/Video Card temps by the way. Only use it for measuring temps though, it also controls your fan speeds or soft overclocks your cpu/video card and if you mess with them you can get much worst problems than what you have now.

its not too bad
intel core duo T7200
RAM 2GB
ATI Radeon X1700 graphics card

and about 2 years old

i never had this problem before.....even when i used to play fallout quite a lot on my laptop