Lost all traffic from google

Have you been sandboxed?

 

How to check my site id sandboxed?

 

Have you signed up for Google Webmaster Tools? (http://www.google.com/webmasters/start/)

From inside your account you can check out how Google sees your websites and you can contact them to request reconsideration. My understanding is that Google is more likely to pay attention to your emails that way since you can prove that the web sites are yours, etc.