If you have the normal virus, you can get popups or something annoying, but for ransomware, it is completely different. Ransomware are viruses that crypt almost all your files. Most popular ransomware is WannaCry. It was infected a lot of computers. Not only computers form normal people, it was infected very important computers like form banks etc. After I said that, we can go into more technical things and really say what ransomware are. They are programs what locks your files with a password. That password is really hard to crack because it is something like: &L>gUhSJ)x7t*g}N. So, yap, it is really hard to crack. Believe me, you do not wan ransomware on your computer.