My screen goes blue while in use sometimes blue after restart as well

while i am using my macbook the screen will suddenly go blue and flash between different blue colors like it is trying to work. sometimes it comes back on but most of the time it stays like that. I have to force shut down with the button and then restart...about half the time it is still flashing blue after the restart and if it does work, it goes blue eventually.

was wondering if there is anything i could do.

dont know if its a problem with the screen or what because the computer continues to work...if there is a movie on, you can here it in the background and the screen just flashes.

thanks for your help

what if i do not have the disk that came with my computer?