BSOD when startup, atikmpag.sys

Please check Windows Updates for updates, install every update available, it may take a couple of times to get them all.
Advised to install the updates in fases in case of trouble.

Diagnostics Test

 Clean boot

Please try the following:

• Open taskmanager
  
  • Go to the tab startup
  • disable everything
• Search msconfig and open it
  
  • Go to the tab services
  • Check 'hide microsoft services'
  • Uncheck all other services
  • Click apply and click ok
• Reboot if asked

See if the problem persist, if the problem does not persist enable in the startup tab in taskmanager 1 item and in the services tab in msconfig also 1 service, reboot and see if the problem persist. Keep doing this until you find the culprit or there is nothing left.
If the problem still persist, try booting in safe mode and see if the problem still persist

You might need to open your laptop and check if the cable for the display is loose. You need to get to the bottom of your laptop, to the motherboard, to find this cable.

In safe mode, the display drivers from AMD aren't used. Because you have display problems in safe mode, I suspect the cable is a little loose what could cause this.

The only other thing I can think of that might cause this is hardware problem as you also stated in your OP.
Just to make sure Windows is not causing this, would you mind installing Windows 7 again?

Clean Install Windows 7

I can't say 100% sure, but I think your motherboard is causing the problem.
My thought is that the connection with the GPU is causing issues, but that doesn't explain the display problem in safe mode which I have no other answer to then something else on the motherboard.