What did you clean the connector / wires with? When it blinked, did the screen go off and then come back on? I know that RAM issue can cause some strange things to happen such as display and no boot.
Does the charge light come on when you plug in the power adaptor?
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=== Update (06/05/2021) ===
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If your pc has two sticks of ram take them out and boot the laptop up and see if it posts. If so then test each stick of ram by placing one in at a time.
What did you clean the connector / wires with? When it blinked, did the screen go off and then come back on? I know that RAM issue can cause some strange things to happen such as display and no boot.
Does the charge light come on when you plug in the power adaptor?