I have a 2nd monitor connected by VGA.
It flickers when I have the computer plugged in to the mains. I took the battery out but it didn;t help. When I disconnected the mains plug, the flickering went away.
Any ideas how I can fix this?
The plug in the wall is 2 prong but the wall socket should be earthed (European socket).
It is a matter of electrical interference where one device synchs with the power source at a slightly different level than another device on the same circuit. Hard to explain without getting into the weeds. Monitors/displays are very sensitive to those minor fluctuations.
Glad it worked itself out. Good luck and happy holidays!