my website has been infected with virus? (Answers: 1) (Comments: 0)

my website has been infected with virus. does anyone know how to remove virus from my website. Even thoughh i have removed some leecher infected directories and files from my admin files still if someone opens my website then its showing apop upp as some html.inf are detected in c/settings drive or programme drives of that particular computer. So are there any free tools for webmasters to check for virus or spyware or malware infections on their website and automatically removes them and is there any way to keep your website free of these spywares or all viruses created by leechers. how to protect my website??????