STEP 7: After you will restart your computer, two new icons in the bottom of the right corner of the screen would appear. It makes the copies of the programs installed by you and if one of them gets infected with a virus, this will help in replacing the infected file so that the program functions properly. STEP 1: Download the antivirus and double-click on the file to launch the installation of Avast antivirus. Unlike other malicious software, they do not replicate, but still could do irreparable damage by taking full control of your PC. A computer virus can severely hamper the performance of your computer.