How to remove this attack from the server?

Hey Guys
I have made website.
But after few months successfully run now its showing virus attack.
Now how to remove this things?
And what to do to avoid this attacks in future?
I have put screen-shot so that u can understand well.

From serverfault Nitz

• If you removed virus and warning is still shown you should go to google webmaster tools and request malware review.

  More info here: http://www.stopbadware.org/home/reviewinfo

  From $pageUsers[$post.author].name

• The only satisfactory solution is to reinstall from a backup taken when you knew the machine was clean. If you don't have a backup wipe it and start again. Properly and fully removing a virus is seldom a simple job, despite the claims made by antivirus software vendors.

  I suggest you enlist the services of an experienced system administrator to help you fix the problems you have and to secure the server a lot better than it is now. This is not a job for the inexperienced, unless you want to go through this again... and again...

  From John Gardeniers