Disconnect all peripherals and confirm if system is working fine with AC Adapter only.
Remove AC adapter, Battery and drain flea power. Remove the battery and charger/ac adapter/power cord from your Dell notebook, press and hold the power button for 20 seconds to discharge any residual current inside the laptop. If still not resolved, follow next step.
Check the AC Adapter status in the BIOS. If AC Adapter status shows Unknown / Not Detected, then try changing the Ac Adapter.
If your system is not able to go to BIOS or boot to Safe Mode, then I would suggest running LCD BIST in order to isolate the issue. To run the LCD BIST (Built in Self-test) Press and hold the D key on the keyboard while pressing the power button, then release both at the same time.
This will initiate A grey screen, then Red, then Blue, then Green then White, to allow you to inspect the entire LCD for color purity on each screen and to better identify defect such as cracks in the LCD or stuck pixels that may not be apparent in a normal viewing mode.
Let us know the results
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