You are infected with malware.

What antivirus and malware protections do you have?

Can you start the computer in Safe Mode and run them?

run malwarebytes in safe mode see steps @  powershell has stopped working

I have heard of this Virus before it is called the cyryto virus, what is does is in encrypts all of your files.   The way i would say to fix it is to format your hard drive using a USB or Disc with your operating system on it.  

Hi,

Try to open your in safe mode. For going this mode,

1. Press F8 while showing your Dell screen appears.
2. Select "Safe mode" 

To give someone a phone number to call, without any indication WHO/WHAT is being called, is not appropriate.   (Is this a private person?   A company?   What are their qualifications?   In addition, if this a paid service, posting here violates DeLL's Terms of Service).

Hello,

If you still have the issue please uninstall the unwanted programs from the system,

If i case you still have an issue, Please call .