i have software on my pc that uses google for certain searches (bit spammy i think) everytime i use google after i use the program it gives me this page. just refresh your ip and all is sorted.
don't worry, delete cookie or (better and) change your browser, then you can xxx google again. I done lots of times on this situation. delete cookie, normally google will give you a message about your computer has malware or something. then delete cookie again, google will show same message but give you a captcha, all you need go is solve the captcha and then you surf again.