They sound like stuck pixels to me.
Try running
JScreenFix over the stuck pixels for a few hours.
From Samsung's FAQs...
"One or two dead pixels out of the approximately 300,000 to 1.3 million pixels on a typical LCD monitor is normal. Generally, then, if you have only a few dark or bright pixels, service is not an option.
With that said, what we do about an LCD TV with defective pixels depends on:
The number of defective pixels.
The location of the defective pixels.
The color of the defective pixels.
The size of the LCD monitor.
If you are having a serious problem with defective pixels, gather the information listed above and call Samsung Customer Care at 1-866-SAM4BIZ. Have the model number and serial number of your monitor on hand when you call. If you are an ASC or SSD, please call 1-800-634-8770 and have your ASC/SSD account number and the model number and serial number of your monitor on hand when you call.
Note: If you have one or two dark or bright pixels, you may be able to fix the problem yourself. For instructions on fixing a dark or bright pixel, see the instructions listed below.
Is There A Way To Fix A Defective Pixel?
If your LCD screen has a bright or dark pixel, it's usually because the liquid in the liquid crystal display has not covered that pixel fully.
To spread the liquid and un-stick the pixel, follow these steps:
Turn your monitor off.
Using a soft microfiber cloth, very gently apply pressure to the area where the stuck pixel is. Do not apply pressure anywhere else, as this may make more stuck pixels.
While applying pressure to the stuck pixel, turn on your monitor.
Remove the pressure. In many cases, the stuck pixel will now work correctly.
Note: Generally, a stuck pixel either remains bright when all the other pixels around it are dark, or only displays one color. A dark pixel remains dark."