Having your website hacked or defaced can be a very stressful time, but don't worry as websites are being hacked all the time and it is very unlikely that you have been targeted specifically.
It is more likely that the 'hacker' has searched the internet using common tools to find websites that have a certain security flaw and then exploited it. This issue is compounded if your website is running any sort of scripts.
The 1st thing you need to do is act - it is irresponsible to keep a website on-line if it could harm visitors.
You need to get professional help - either from us, your web designer, your hosting company or any other web professional. If your website can be restored to it's former glory from a back-up copy then great, but sometimes websites cannot be restored and the files that have been 'hacked' need repairing.
You also need to consider the PR impact to your business should your website be hacked... Not only does a hacked website look un-professional but you may also pick up a penalty from the search engines such as Google and Yahoo! if you do not act quickly enough.
If you do get a penalty from the search engines then visitors trying to visit your website will see screens like this:
This is obviously very damaging to your business BUT it is recoverable, you need to clean the site and then let the search engines know that all is well again - we can assist you with this if you are unsure.
Our website virus removal service has been moved to it's own dedicated website here www.websitecleaners.com