Some viruses have the ability to prevent the installation of an antivirus or block any antivirus program that you have installed on your computer. Virus infection can be made to override any attempt to clean the system, so it can block new installations of cleaning programs or even cancel any program that was previously installed.
If until now the only way to solve this problem was directly format and install Windows from scratch, now we will have a program that will allow us to at least make one last attempt: Malwarebytes Chameleon.
The operation of this program is essentially simple, because what makes MalwareBytes Chameleon is installed to conceal all your files to fool the virus as part of the infected files. Chameleon offers three installation attempts, until you find one that works. Once we install anti malware, we can make the cleaning of the virus.
The program is not foolproof, since we have a virus that is too sophisticated and recognize that we are making an attempt to force installation. However, it is preferable as a last attempt to have to reformat and lose all our files.