What precautions should be taken while using various types of software on the computer?

While using various software on computer we should have to take following precautions: When we are installing the software we have to check whether the site is authenticated or not. We have to use only one software at a time otherwise running many software in background may slows down the speed of computer. To avoid data hacking we must have to installed antivirus protection in computer. While using any software we have to use it according to the rules and regulations only otherwise it may harm to the computer.