Welcome to the Community. 7 Beeps means its a processor failure. Contact Dell Technical support in your region for a replacement.
Did you change the Processor?
The Manual Says Processor Failure.
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Try reseating the memory. Dell is know for loose memory
Thank you for your speedy responses - I will replace the processor
hi David did you get your laptop repaired? if so how did you replace the CPU as i have the same problem