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Someone had what sounds like the same issue as you, recommended things to try within:

https://www.dell.com/community/Inspiron/Screen-Black-After-Dell-Logo/td-p/7698859

But the screen might not be at fault here, given you can see the Dell logo just fine?

Can you not partially disassemble it yourself and see if the connector has not just come loose? Though they may now solder it on to make it harder for home repairs and thus generate them more money....