Laptop screen keeps flickering after removing hdmi cable

[Reinier VD]

I recently rebooted my laptop to factory mode, updated graphic drivers for my AMD radeon HD 6550m, but now whenever I remove the hdmi cable of my second monitor the laptop screen gets this annoying black line flickering. (single pixel black line flickering/appearing on the screen for a split second multiple times) mostly when I move my mouse.
removing the drivers doesn't work, installing older drivers doesn't work, I'm in a pickle.

However if I re-insert the hdmi cable nothing is wrong.

Laptop: Acer Aspire 7750G, Radeon HD6650M

 

[Narzter]

Have a look at your display setting (hint, hint)

 

[Reinier VD]

Have a look at your display setting (hint, hint)

I tried everything in my display settings, 16 bit helps a little bit, but that's pretty ugly.
Also when I play media (movieclip) the stuttering increases.

 

[Narzter]

If you have Nvidia control panel, make sure all other displays are disabled. Install if if you don't have it. Play around with the settings a bit. I think you should find something there. If nothing helps, there must be something wrong with your built-in laptop monitor.

 

[Reinier VD]

If you have Nvidia control panel, make sure all other displays are disabled. Install if if you don't have it. Play around with the settings a bit. I think you should find something there. If nothing helps, there must be something wrong with your built-in laptop monitor.

Nvidia control panel wont work with my AMD videocard.
The screen is perfectly fine if I hook up another screen/tv with an hdmi cable.