A Dell laptop running Windows 7 Proffessional that has been in use for more than 2 years shows horizontal lines on display seconds after turning on as shown in the video. Why?
What I did was stop using the accumulator for a few months. One day, I put the accumulator in while the laptop was previously powered by cable only. It functioned normally for up to 50 minutes, after which horizontal lines of white, black, pink and green colors suddenly appeared on display. it lasted for about 10 seconds and then screen was black. Caps Lock LED started flashing and Num Lock LED and some other LED turned on for the whole duration. It turned itself off in the end. The cable adapter was receiving power, it's LED was on.
After that, the laptop was turned on absent accumulator, powered by cable only. Screen was black, LEDs were flashing or turned on.
Now, whenever I turn on the laptop, I get the horizontal blue lines in the video.
I'm wondering what could be causing them. Could it be dust on the mainboard? Maybe a RAM board out of it's slot? Or a shortcircuit on the mainboard / video board?