Macbook keeps freezing and fading to white.
Originally this started happening every now and again but in the last few days it's happening all the time and making using the MacBook difficult or sometimes impossible. It's hard to explain but basically everything freezes and then fades to white, until eventually everything disappears. I've managed to take a photo from my phone of what happens.
http://i46.tinypic.com/29m4z2f.jpg
Just wondering if anyone has any idea what the problem is and how I can resolve this issue, thanks for your help.
Macbook, Mac OS X (10.6.1)