Unable to install ComboFix: PC has Virut Virus

When trying to install ComboFix Anti-Spyware, I get the following popup alert message:
!! ALERT !! It is NOT SAFE to continue.
The contents of the ComboFix package has been compromised.
Please download a fresh copy from:
https://www.bleepingcomputer.com/combofix/how-to-use-combofix
NOTE: You may be infected with a patching virus 'Virut'
I have tried to re-download and installed ComboFix but it doesn’t help. I have not found anything that will help me find 'Virut' and how to clean it. I tried going to the site where I can download a fresh copy of ComboFix and followed all the instructions given but after downloading and trying to install it again, the same error incurs. What could this be? Am I infected with a spyware? What should I do?
