Ransom:Win32/Bastaloader.Lk!Mtb is a type of ransomware that infects computers by encrypting files and demanding a ransom payment in exchange for decryption. It typically spreads through malicious email attachments, infected websites, or software downloads. Once a computer is infected, the ransomware will display a message on the screen informing the user that their files have been encrypted and providing instructions on how to pay the ransom to receive the decryption key. It is important to regularly back up your files and keep your antivirus software up to date to protect against ransomware attacks like Ransom:Win32/Bastaloader.Lk!Mtb.