I had suddenly experienced a big drop in my rankings, in fact I do not even qualyfied for the important words...to find my site in google I have to serach a particular phrase in my web...so, how can I know if I am banned, sandboxed, penalized or is just a drop? Thanks
It sure sounds like you are penalized. I think it is pretty hard to prove that you are penalized though. If you can find your website for a particular phrase then you definitely aren't banned. How old is your website? If it is fairly new, it may be sandboxed.
Could just be the natural ebb and flow of the SERPS. Give it a few days you just might gain it all back.
There are a couple of major penalties you can check for. The -30 and the -950 (or end of results) penalties. Do a google search and you can get some information about what the symptoms are and what you can do to get out of the penalty.