MBP video issue

Hi,

recently my 1 year old MBP started to act strange. Randomly the machine locks up and all I can do is keep the power button pressed until it shuts down. The after shutdown at first startup it goes to the Apple Logo screen and then it reboots. At first I thought my machine is overheating but that is a bit strange since I have the smcFanController installed and my fans are at 6000RPM's.

That was 1 week ago, first lookup in 1 year. Since then however just before locking up my screen displays like a patter of short lines with the same color as the active background. For example if my background is has red, white and black then I would get a patter with short oblique lines (about 45 degree angle) with 1 red, 1 white, 1 black and so on all over the screen.

This is becoming very very annoying as sometimes it happens of the middle of something important and I lose all my work. Any ideas what can it be ? Could this be a video card chipset issue or something else ?

Thanks in advance for any help.