Well...to go a different route than thinkpads user, I dont think the hard drive has anything to do with the problem. I would say that this sounds to be a video/motherboard problem. Could also be a screen problem itself.
You dont need the hard drive to get the laptop to turn on and boot up or even see anything on the screen. So if you are getting display/graphical issues prior (ie: bios, boot up, post test, memory test etc) to the system accessing the hard drive, would lead me to believe motherboard or video/screen problem.
You said you replaced the motherboard already? And the problem persists? The original motherboard may not be at fault then. And would point towards the Screen. I believe the A31 has a built in video processor on the motherboard right? so that would/could cause the problem as well...
Actually one problem comes to mind as well...An overheating or burned CPU (that has been friend) you may still get some video as you describe but have video issues etc. So you may have a CPU issue. Does the system run hot? or did it run hot at one time?
