I have also experienced a similar problem. It's happens just a day ago on the 4th of April 2020.
I was downloading a supposed update and after it was done, my computer started opening random Google tabs and kept releasing text boxes. I thought it was weird and thought nothing of it.
Then, as I was about to start to do some work, I realized that all my files, such as photos, notepads and others had been encrypted and I could not open it. Upon attempting to open it, the system asked me what program I would like to use to open it.
All my files ended in a .mado and so I panicked and realized I downloaded a malware. I quickly downloaded an anti malware and got rid of it, but my files are still encrypted and I don't know what to do.
Also, sometimes I boot up my pc it turns into a black screen. I could really use some help. Thanks.