Adding to the confusion are reports that banned pages are sometimes showing a white bar, sometimes gray, and sometimes even green. We're not sure whether Google is having technical issues or if Google is purposefully crippling the PageRank feature to make search engine optimization more difficult.
Whatever the case may be, we can no longer consider the Page Rank feature of the Google toolbar to a reliable indicator of whether or not a page has been intentionally dropped (banned) from the Google index. Fortunately, however, there are much more effective ways to determine if your site has been removed from Google.
The easiest way to tell if your site has been banned and completely removed from Google's index is to enter the following into the Google search bar: 
site:www.yoursite.com
(replace www.yoursite.com with the domain name of the site you think may be banned)
This will show you most of the pages that Google has indexed for this domain. If this doesn't produce any results, try searching for some text such as an address or phone number – that you are sure is unique to pages from your site and were previously indexed by Google. You could also try searching for a short piece of text. For example, to see if this page is indexed, we might search Google for the opening phrase of this article...
Reasons why Google drops web sites from its index
- The most common reason why web sites are removed from Google's index is that these web sites use shady tricks to get higher search engine rankings.
If you use cloaking, hidden text, doorway pages or any other technique that's only for tricking search engines then you can be sure that your web site will be banned as soon as Google finds out. Don't try to cheat Google, it will backfire on you.
Even if you don't use shady tricks to optimize your web site, your site might be removed from Google's index if your web site was down when Google tried to index it.
If you have a new web site, or if you have made major changes on your site, your web site might be put into Google's sandbox. You then just have to wait until it comes out of the sandbox.
