This is not the problem or infected or anything else. This is just the warning that you are searching not in a normal way or use any tool.
Apart form above mentioned, I wold recommend you doing these to got it fixed. 1. Clear cookies from your browsers 2. Reset your modem / router and let them get new IP address. This could help avoid prevention from Google in most cases.
Thank you all for your support... I think it must have been a SEO tool I had on Chrome... Uninstalled every add-on and now this problem is solved! Is there a page rank tool which doesn't cause this problem?
I kept having this problem when I was using the google search operators (link: allinurl: etc) very quickly when checking for a variety of keywords. Usually just a quick ten minutes and maybe a clearing of the cache seemed to fix the problem.
This happens mainly because you must be search too many results in google for your websites like link:yourdomain.com OR site:yourdomain.com OR info:yourdomain.com or trying to check for the same keyword results again and again. I have around 200 blogs/sites and I need to check all the sites information on google, so yes I do get such type of errors too from google. But it is not something wrong with google, but its me that doing lot of search results on google from one ip
You running SEOQuake? Turn it off, wait a little while then try again. Quake did that for me I have to keep it off most of the time. All that extra info you see pop up on google from Quake, all that is automated queries.
It happened to me also this thing a couple of times, it happened also when i was manually searchingbut i was surfing many pages in a relatively short time or when i was doing keywords research with more than one seo tool...