it part of the system board. but i would connect a monitor to the laptop and see if the video out port has the same errors.a lot of times lines in screen is the screen or inverter board issue. I would pull the hard drive and 1/2 the ram and see if it boots to the bios and or a hirem boot cd without any errors. some laptops use onboard ram for video ram..if the ram stick is lose or bad..can cause issues. if the hard drive is dead it can also pull more power then normal causing mb issues.
i did everything you said ans then i reinstalled the amd graphics driver in safe mode an suddenly everything started working again i can even boot up xp normally
but i will test this thing more before i give it back. i also have an extra quastion what does the middel fan cool i have no idea