What?? I have never heard Google reporting about site hacked. Check for the issue of spam. Please stop advertising when somebody is in problem. It is totally bad idea.
Even if you have a good anti-virus installed on your system there are lots of encrypted viruses that your AV software can't detect so its better to just reinstall your OS ( thats the only sure fire way ) and get a good internet security suite like ESET Smart Security and be careful about any files you run online. If you are not on a very popular, reliable web host then its better to switch that as well.
i have a virus too that i need someone to resolve. The advice from ferris is good (based on what i have seen in the past). Talk of simply changing host is rubbish, what's the point of doing that when u have infected files? ur simply transferring the problem!
Changing hosting providers isn't going to help. We've cleaned over 64,000 websites and rarely is it the fault of the hosting provider. Nobody ever wants to believe that it's something they neglected to do. Many websites are hacked because they haven't been updated or properly secured. For sites based on Joomla, Wordpress, etc. KEEP THEM UPDATED! Don't put it off until you have time, MAKE TIME. If not, you'll have all sorts of time when your site is down after hackers have found the opening. Also, with Joomla and Wordpress, since they seem to be two of the most popular, check the plugins and keep them updated as well. Joomla publishes a Joomla vulnerable extension list - read it. We see many websites infected repeatedly until a specific plugin is either updated or removed. Also, when Google sends you an email saying your site is infected - take it seriously. Keep in mind, that any service that scans your site from the outside, via a browser or some other automated way, will never find all the backdoor shell scripts that hackers like to use to re-infect your website - never. They can't. All your files need to be downloaded and scanned. That's the only way you can find all of the backdoors. If your site is based on some software like Joomla or Wordpress, you might want to delete your entire site, then upgrade it and re-install. Oh yeah, you'll also want to export any SQL databases and have them scanned as well. Hackers love to inject their malware into SQL databases too. When they've put a backdoor shell script on your site, they have access to every password used on your website - not your cPanel or FTP, but all the other passwords. At that point they don't even need to use SQL injection, they can simply login to your database, they have the username and password, and insert the code they want. Post back if you'd like some real answers to your questions.