System does not boot and is stuck on DELL Logo

Unplug the system, remove the base cover and disconnect the battery from the system board.  Hold the power button for 30 sec.

Then reconnect the battery and try again.  

There's not much more you can do unless the system can boot, and if this is a 2-in-1 with a soldered in drive, there are several possible issues.  If the drive is the faulty part, the data may not be recoverable at all, and even if it's not, the question is whether the data has enough value to justify the cost of a recovery service (this will be in the thousands of dollars if it's even possible).

Thank you for your response. Maybe I am hoping still that all my data is not lost. In my conversation with Dell support, they say to send my PC to them but need to back up the data as they are not responsible for any data loss.  I told them that I cannot even get access to the drive else I would have done the recovery and just trash this PC.  Dell instead referred me to 3rd party recovery which as you said charges up to thousands of dollars.

Get a repair estimate from somewhere like GIllware -- they are very reputable.  That said, this is going to involve extensive work, and will easily run a few thousand dollars.  Only you can decide whether the data is worth that cost.