The virus that changes your password is a type of malware known as ransomware. Ransomware is malicious software designed to infect computers and encrypt files, making them inaccessible to the user unless they pay a ransom to the attacker for the decryption key. In some cases, this may include changing passwords on accounts associated with the infected device in order to further limit access until the ransom is paid. It's important to be aware of this type of malware and take steps such as backing up data regularly and keeping antivirus software up-to-date in order to protect yourself from it.