Hello my name is***** am sorry you have encountered this kind of problem. Was it prompting you to do this before windows 10 was installed?
Usually when this happens it means that the previous version of windows may not have been activated. Have you restarted the machine since this has happened to see if it registers correctly? If it fails to do so windows may need to be reinstalled again so it's activated and then windows 10 reinstalled. Also what is the make and the model number of this machine?
I see, have you contacted them to get the hard copy of the recovery software that should come with it, if not you can actually have dell send you the software I believe it costs around $25 it would give you a registered copy of windows so you can do the windows 10 upgrade. Until then you can try and go back to what you had. It doesn't always work but sometimes this does. You would have to right click on the start button then go into control pane. Then click on backup and restore to windows 7. You should be able to follow from there. I would highly recommend getting the recovery software from dell.
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