I have no experience. They send me an email saying that they have compromising info from internet activities and all my contacts etc. If I do not pay they will send this compromising info to my contacts.
Weak, I know, but I have no clue. Nothing is frozen.
However, yesterday my PC was rather slow and I could hear it being unusually. Then one website tap changed to big red screen allegedly from Microsoft saying that machine must not be reset etc as its infected and resetting could do more harm. It gave some telephone number to call. It froze my browser too. I ignored all this and restarted and all was ok again. So that in combination with that email makes me a bit wary.
I ran AVAST and Malware Bytes and they found nothing.