"THIS WEBSITE MAY BE HARMFUL TO YOUR COMPUTER"

Google has effective trojan recognition and will throw this warning on a website that is potentially dangerous.

 How does my site get infected?

• Use of old PHP scripts with security holes in them (always use the latest stable version).
• 777 permissions on files leave the back door open to write to a file.
• Using a pirated copy of an HTML editor where a trojan is embedded in page HTML script and uploaded to the website.
• Password breach

What do I do?

• Scan the site on your computer using an effective antivirus program like NOD.
• Look for java script embedded in the code.
  • Usually the script will be displayed in ASCII to fool obvious destinations that are not related to your website.
• Manually remove code and change password.

Removing Google warning message on Search Results Display

• Once your site is clean and has been uploaded to your hosting space, log into Google - if you don't have an account, now is the time to open one - it is free.
• Go to Webmaster Tools - click here
• Add your website URL and verify it
• On the Webmaster Tools Home page, select the site you want.
  In the Parts of this site may be distributing malware message, click More details.
  Click Request a review.
• Read more about Malware and infected websites