when you said, "i got virus many times on many website" what sort of virus- trojans/rootkits/iframe attack? Most of the times, worm resides in some of the client side PCs you use for accessing the ftp/control panel accounts of your hosting server. When you type in the username and password for the ftp/control panel account, the worm silently reads the credentials, accesses your ftp account and infects the files in the server. It infects all your websites files. Make sure that you have installed all security updates in your local system(update all antivirus and try also some soft like malwarebytes anti-malware). Also, you must have a strong password with special characters, letters, and numbers (at least 12 characters). Only temporarily store this password, do NOT store in browser.