My friend has bought a used mac pc. It is working well. We had installed a lots of application on the same and few games also. The system worked well for around 2 months. Now I can see vertical lines on the monitor. This are exactly in the center. It is very hard to use the system in that way. We cannot even read things behind those lines. This appear instantly. Before it worked quiet well. I tried to restart the mac a number of time but those lines are constant. I hope this is not a major issue.
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