First off, if your Website was hacked, you have our sympathy. It's really frustrating - not only because it's troublesome to your visitors, but it's really difficult to completely remove the hack.
There are many ways to resolve the issue, but we're going to cover the fastest and easiest way to fix your website.
Unless your website has obviously been defaced, go to http://www.google.com/safebrowsing/diagnostic?site=your domain name — if your website has been hacked, it should show a warning here.
If this doesn't show an error, it's possible your website has still been compromised, but it's less likely.
If your Website's been hacked, you need to immediately change all of your passwords. We recommend using strong passwords.
To make sure you use the right instructions, find out what type of hosting account you have.
|Hosting type||Password resets|
|cPanel||Primary FTP, secondary FTP, databases, apps like WordPress|
|Plesk||Primary FTP, secondary FTP, databases, apps like WordPress|
|Web & Classic||Primary FTP, secondary FTP, MySQL databases, MS SQL databases, apps like WordPress|
If you have a backup of your website (and database) that you know wasn't corrupted, you should re-upload it to your hosting account.
It's nearly impossible for anyone to reliably remove malware from a website by hand. To remove the compromise from your files, we recommend using an application like SiteLock Professional. Using its SMART scan technology, it will not only find any compromises in your files, it also removes them.
To prevent your Website from getting hacked again, you should identify how your Website was compromised. There are two types of weaknesses: passwords and structural problems.
Most hacks happen because the attacker was able to guess your account's password by brute force. By simply changing your password (and using a stronger one this time), you can prevent these attacks from succeeding in the future.
These types of weaknesses require thorough testing to identify. There's a lot of security software that can perform these types of scans but, again, we recommend SiteLock Professional. It can identify a number of different issues, as well as help you fix them.