My 2007 macbook pro display is going a bit weird?! Any ideas?

I bought a second hand 2007 macbook pro last year and has been in perfect working order. Except today it has decided to do some weird things.

I was watching something on lovefilm on full screen and suddenly the picture froze with a chequered pattern all over the screen although the sound played for about a minute. The chequers then disappeared but i could not come out of the full screen.

I switched off the laptop then waited and switched it back on and the apple is now covered with the chequered screen!

I took out the battery and back in and tried again and each time i had something different: several different looking chequered screens, a split screen with the pattern and then a constant blue screen.

I left it for a while and then tried again and it loaded up fine! Then i went back onto the video i was watching and the whole situation happened again.

It keeps happening. Is this linked to the website or a fault with the laptop?

Any ideas?

Thank you