|"Do i need a separate anti-virus program if i have Trend Micro Internet Security installed already?"|
Extract from the Trend website.
"Note: It is advised to install only one version of an antivirus program on your computer. Having multiple antivirus programs installed at the same time can cause performance issues and make your computer more vulnerable to threats."
"Hitman pro scans when I start up computer"
Hitman is not an AV, it is a program to help you remove stuff, once you are infected., just like Malwarebytes.