OK, the first thing to remember is that Google AdWords and Google Search are two completely separate entities, they are just displayed on the same search page when you make a search.
Many times you here “I removed Google AdWords and lost all my rankings” with people touting conspiracy theories on how Google makes them keep paying for AdWords otherwise they will lose their organic rankings. This is complete nonsense however!. Read Google’s official line on this subject.
Just so you sleep well at night I would like you to know that there is no big Google AdWords conspiracy and anything that happens to your web sites rank in the organic listings is completely separate and unaffected by Google AdWords .
Google Organic search uses the search engine spider Googlebot. Google AdWords uses the search engine spider Google Mediapartners. Just check your server logs and you will probably see both at one time or another.
Google AdWords uses a completely different ranking algorithm and pricing model to rank Ads than the Organic search uses. Google AdWords uses something called Ad Rank which is based on a quality score and a cost per click value.
Another interesting fact is that you can have an AdWords account without your site being indexed in the Organic search. Surely this fact alone should convince people the two are not related.
So, you can rest safe in the knowledge that your Google AdWords (or AdSense for that matter) account has no effect positive or negative on your Organic Google search results.