These may either be burnt or stuck pixels. There are many methods of removing stuck pixels on the internet. Choose the one that best suits your purposes (ie using a program, repeatedly playing a video, etc)
You could check your fluid levels to see that they are properly topped up. Having low motor oil and other essential fluids might be causing unnecessary friction on piston heads. A loose or slipping belt on the idler pulley might also be the reason. You can check for any major movement on the pulley wheels or squeaks coming from the belt to verify this. Worst case scenario might be an engine problem such as losing compression in a cylinder, a damaged head gasket, or worn crankshaft.
The easiest fix would obviously be to check the ribbon cable. After all, the cable might have simply become dislodged. My advice would be to start with the easiest fix and work your way up to the hardest. Did you try taking pictures with the camera after you dropped it? If the camera can still properly take and save the photos, you would at least know that your shutter box, sensor, and logic board aren't damaged.
The problem most likely seems to be the battery, as other contributors have pointed out. The most surefire way to check if it indeed is a battery problem would be to use a multimeter and check the battery's voltage. It should be at around 12.6 V. In this case, simply jump start the car and let the alternator charge the battery up. Once you start it up, turn on the headlights, heating, radio, and anything else that uses battery power. If you get a 'check battery' light or the engine stalls, then you know it's most likely a problem with your alternator.
I would recommend the same method as Steffen recommended above. However, if there is no dust and the problem persists, there may be a problem with your CPU. In that case, you could try upgrading your CPU (one with a same connector), or if it is not upgradeable, use a laptop chill mat or some other cooling accessory.