My HP 2509m LCD monitor is flickering and one half of the screen is brighter than the other.
unplugging power, factory reset, disconnecting and reconnecting the cable
Checking on whether the cable was connected was a good idea, I would have recommended that be done.As it is, it sounds as if your monitor has either a backlight or a power supply problem. In either case it will require a trip to (or being sent off to) a repair shop to fix the problem.I advise, first of all, going to http://h10025.www1.hp.com/ewfrf/wc/weInput?lc=en&dlc=en&cc=caand seeing whether your monitor is still covered by HP's manufacturer's warranty term.If you need further advice about this case, please let me know and I will try to help.
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