It sounds like the Reset has screwed your system but I don't know why unless there was also an underlying problem.
I assume you are using Win 10 and did the computer come with it pre-installed ?
I'm thinking along the lines of a factory reset.
If it didn't come with Win 10 then you will need to contact Dell for a Recovery disk to factory reset it.
There's usually a cost for this.
You can then upgrade back to Win 10 through -
https://www.microsoft.com/en-gb/software-download/windows10Use the May 2020 Update option.
You will need to reinstall your programs but unless you had your personal stuff backed up, then I'm afraid you will have lost it.
However, there is one other thing you could try if you can use a friend's or relative's computer and that is to create a Hiren's Boot Disk to see if that will get Windows back up.
Use the 15.2 download -
https://www.techspot.com/downloads/6966-hirens-bootcd.htmlTap F12 as you switch on, use the cursor keys to select the DVD drive - insert the Hiren's disk and press enter.
You may have to press any key when prompted to boot from CD/DVD.
You will need to follow the same procedure if you have to use a Dell Recovery disk.