Horizontal lines/Flickering on monitor when laptop is on AC power

I have a screen flickering problem on my Toshiba Satellite A100 and i have connected another Samsung monitor to this laptop and seen that it shows horizontal lines moving up and down when i connect it to an AC power. I have installed a windows 7 on this laptop and it has an Intel Duo Core 1.6Ghz processor with the 2 Gb RAM. I do not get that why these lines are coming only when i connect my computer to AC power supply.

I have seen this same problem but not with the additional monitor as my laptop screen itself was flickering because of the AC power supply. Then i have found that there was fluctuating power supply behind this problem and this could only be solved by an electrician. So i called him and now my laptop is working perfectly with the steady screen. I think this should be your problem as well so check your connections with an electrician.

If your laptop is flickering when you remove the laptop charger from it then there would be a ground loop problem as this is the main reason behind this behavior of monitors. Actually your monitor is grounded using the Three Pin Plug and laptop is not grounded. Here what you have to do is unground the monitor by using the spare power cable or you could just use an adapter that only has 2 prongs but accepts three.

It could be the RAM issue as this kind of behavior has been seen by the most of the monitors when they do have a sufficient support from the RAM inserted in to the computer system. I suggest you to check for your RAM by inserting it into another computer or you may use some other RAM to try it on your laptop and check whether this problem goes off or not.

I think you are facing this flickering problem because of the screen refresh rate. The horizontal lines about which you are talking could come because of different refreshing rates of your laptop and an external monitor. It could also come because of the poor grounding for which you may unground your monitor but let me tell you that you may get slight shocks from the monitor.